Healthy Skepticism Library item: 3863
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Publication type: news
Swan N.
Cancer Screening - Benefits and Harms ( three part series)
Health Report ( ABC Radio National - Australian Broadcasting Commission) 2006 Mar 6
http://www.abc.net.au/rn/healthreport/stories/2006/1582008.htm#
Keywords:
cancer screening tests breast cervix prostate PSA mammogram colorectal
Notes:
Ralph Faggotter’s Comments:
This three part radio series looks at the pitfalls of cancr screening tests.
There are very few really good Health screening tests in the world and there are a lot of bad ones.
Consumer beware!
Full text:
Cancer Screening – Benefits and Harms, Part One (Repeat)
Listen Now – 20022006 | Download Audio – 20022006
Most people would say that screening to find cancer early is a good idea. Well, maybe not so good. It could be that finding small cancers earlier and earlier is doing more harm than good. According to Professor Gilbert Welch from Darmouth Medical School, New Hampshire, USA, cancer screening is a two edged sword with important harms as well as benefits.
This is part one of a special three part series which looks at how screening can unearth cancers you’d rather not know about, as well as other drawbacks of cancer screening.
This series is presented by Associate Professor Alex Barratt of Sydney University and was first broadcast on 22nd August, 2005.
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Transcript
This transcript was typed from a recording of the program. The ABC cannot guarantee its complete accuracy because of the possibility of mishearing and occasional difficulty in identifying speakers.
Norman Swan: Good morning and welcome to the programme.
This morning on The Health Report, the first in a very important three part series that you mustn’t miss because it affects us all.
We in Australia spend hundreds of millions of dollars a year on cancer screening from breast to cervix to bowel to prostate – all in the belief that picking up problems early is the best thing to do.
Well, this series made by Associate Professor Alex Barratt of the School of Public Health at the University of Sydney suggests we all need to think twice about this. Alex is a physician who researches this field.
Montage:
When you go there you wait in a rather depressing area and then they get these huge plates of steel and your breast is squashed. Absolutely squashed. And then you’re told it’s gonna be squashed more.
I had my first PSA test at the end of 2000. It might have been 15 or 17 or something like that. And the doctor was saying to me, you should go and see a urologist and I said, well, I’ll see him in January or something like that and he said, I think you should go earlier.
I was reaching that wonderful milestone of turning 40 and I just thought I really should have a PSA test.
They rang me to say they needed to do some new films. They took the new films and then they rang me a couple of days later and said, look we made an appointment for you, there’s a problem and I said, well, that’s fine because it’s nothing.
Well, I went and had a colonoscopy and was honestly thinking I would wake up and be told everything’s fine, it won’t be me, I’m healthy and don’t have any symptoms, I live a good lifestyle and I was quite devastated to realize that I actually did have bowel cancer.
Gilbert Welch: Cancer testing is a much closer call than is usually acknowledged in either the general press or by professional organizations in medicine. On one hand the benefits of screening have been widely overstated, on the other the harms have been largely ignored and I think we all need to understand that cancer testing is a two-edged sword. The public has really only heard about one side, that is that it’s always good to have another test and the truth is we’re more certain about the downsides of many tests than we are about their upsides.
Alex Barratt: Dr Gilbert Welch is a physician with the US Department of Veterans Affairs and Professor of Medicine at Dartmouth Medical School.
Before we go on, nobody could have missed the headlines about Kylie Minogue having breast cancer. Almost certainly Kylie had her cancer diagnosed because she or her doctor noticed a change, maybe a lump. That’s not what we’re talking about here. If you’ve noticed a change, like a breast lump or abnormal bleeding, you should see a doctor. Tests are good at diagnosing cancers that are already causing symptoms, and all doctors agree that early treatment for symptomatic cancer is important.
We’re talking about having cancer tests when you’re healthy. This is called cancer screening.
I should also tell you that I work at STEP. That’s the screening and test evaluation program at the University of Sydney. I’m one of five researchers who run the program. In the final part of this series I’ll tell you about some of the work we’re doing at STEP.
But right now I’d like you to meet Rosa. Rosa had her first screening mammogram when she turned 50. Her first two visits were fine, but after her third screen she was recalled for more tests.
Rosa: The next day I went back and all these other women are sitting in the waiting room as well. And my turn came. And when the doctor walked in he had a counsellor with him, and I knew I had big problems. He said there are signs of breast cancer. It’s DCIS. We can leave it or not leave it, it’s up to you.
Alex Barratt: Later, more on DCIS. That’s ductal carcinoma in situ, and what Rosa chose to do.
But the downsides of screening that Dr Welch mentioned earlier aren’t limited to breast cancer. They occur in prostate cancer too. Four years ago Noel had a urinary tract infection. As part of his medical care he had a PSA. That’s the prostate specific antigen, often used as a screening test for prostate cancer. It came back high so his doctor did a prostate biopsy.
Noel: They found the smallest amount, but it was enough to confirm that I had cancer. And I think that was probably the biggest shock. When you hear you have cancer it really knocks you for six. The worst thing about this was that it put me into a big dilemma. Should I do something, shouldn’t I do something. Could I live with it or should I get radiotherapy or should I get a radical prostatectomy.
Alex Barratt: The health messages about screening have been effective. Research shows that men and women rate cancer screening as one of the most important things in their health care package. But maybe we’ve only heard half the story.
It’s possible that people like Rosa and Noel are having cancers found by screening that they might prefer not to know about. I know that sounds wild. Surely it’s good to find and treat cancer early, we’ve been taught that for years. But what’s becoming increasingly clear is that some of these screen-detected cancers are very different to cancers that cause symptoms.
Dr Welch thinks that finding many of these early cancers is the number one harm of cancer screening.
Gilbert Welch: It is by far the least understood downside, and I think the most important. Whenever we test healthy people for cancer, some people are diagnosed with cancer unnecessarily. It’s the side effect of the test. And you say geez either people have cancer or they don’t. And in fact there’s really two definitions of cancer that are floating around. One is what most patients and most doctors and most of our audience immediately think of when they hear the word cancer, and that’s a relentlessly progressive disease which if left untreated will ultimately lead to death. But of course that’s not in fact how it’s diagnosed. It’s really diagnosed by its pathologic appearance, what it looks like microscopically. And so those are really two different definitions.
In years past these two definitions worked quite well together when pathologists were only given big tumours to look at. They were clearly invading surrounding tissues under the microscope. There is no doubt that these were bad cancers. But as we start looking for cancer early we’re sending them smaller and smaller specimens, and they’re really looking at just a few cells. And what is happening now is that we’re finding these small abnormalities that meet the pathologic criteria for cancer, but would never bother patients if they were left alone.
Now what’s happening to these small cancers? Well they either never grow at all, or maybe even get smaller with time. Or they grow so slowly that people die of something else before the cancer ever causes symptoms. That’s the real conundrum with cancer screening. If you try to find cancer early, all of a sudden you find a lot more than anyone ever thought existed. And that’s one of the things we’re beginning to learn as we look harder for cancer, that there’s an awful lot of cancer out there that we never knew existed. About a third of all adults will have some pathologic evidence of thyroid cancer; about 40% of women in their 40’s will have microscopic evidence of breast cancer, the so-called ductal carcinoma in situ.
Alex Barratt: I’m sorry, you said 40%?
Gilbert Welch: Yes I said 40%, and that comes from an autopsy study of women who have died from something else. And when pathologists carefully sectioned their breasts and looked for microscopic evidence of cancer they found about 40% of them had microscopic evidence of breast cancer. And we’ve also found out that older men, well over half have microscopic evidence of prostate cancer. So there’s a tremendous reservoir of undetected cancer out there. And if we start looking hard for cancer then we start to find it. And we tell a lot more people that they have cancer than would ever die from it.
The place where all of a sudden the front line physician recognised that we had a problem was in prostate cancer in the United States, where we introduced this blood test, the prostate specific antigen or PSA. It was widely dispersed across the country. And we saw an incredible rate of rise in the number of prostate cancer cases diagnosed over a very short time period. And all of a sudden we realised we were finding many many more men with prostate cancer than would ever be expected to die from it.
Alex Barratt: I think lots of people have heard of this idea that there’s a lot more prostate cancer than one would find if you didn’t do screening. But this is new to say that the same concept applies to bowel cancer screening, to breast cancer screening, to cervical cancer screening. And yet I think that’s what you’re saying?
Gilbert Welch: That’s absolutely right. There may be more or less in different types of cancer. But in general whenever you look harder for the disease you tend to find more and you tend to introduce people who otherwise would never be bothered by their cancer, they tend to be diagnosed with cancer.
Alex Barratt: Dr Gilbert Welch is a physician with the US Department of Veterans Affairs. So, cancers that don’t matter? Cancer that would never bother you? Is he a lone maverick? Well probably not. Some very respected researchers agree with him.
Paul Glasziou: I’m Paul Glasziou and I’m the Director of the Centre for Evidence Based Medicine at the University of Oxford.
Alex Barratt: Gil Welch says that maybe I shouldn’t be tested for cancer. What do you think of such a suggestion?
Paul Glasziou: I’m considering whether I should be screened for colorectal cancer, but I can give you a long list of cancers that I definitely don’t want to be screened for. As a non-smoker I certainly wouldn’t want to be screened for lung cancer. Prostate cancer is obviously a difficult one, but again I’ve taken a conscious and informed decision not to be screened for prostate cancer. I could name a million others, stomach cancer, oesophageal cancer, mouth cancer, brain cancer. We don’t screen for most cancers.
The worry of that is that they would find things to investigate which would cause me worry, potentially harm, but with no potential benefits.
Alex Barratt: So do you agree with him that the benefits of cancer screening generally have been greatly overstated?
Paul Glasziou: Yes I do. Probably the most dramatic example of this is lung cancer screening. It’s been tried in cigarette smokers. Several good quality, large scale, randomised trials. It made absolutely no difference whatsoever. If we look at other types of cancers though, where there is some benefit such as breast cancer or screening for large bowel cancer, even there the benefits haven’t been huge. We’re looking at reductions of something like 25 to 30% in mortality from these conditions. That means that most people who get screened who are going to die of their cancer will still die of their cancer. We’re getting nowhere near 100% benefits.
This is in relative terms. When we look at the rarity of cancer and think about the absolute benefit, we’re actually talking about screening usually thousands of people in order to prevent one death quite some time down the track.
Alex Barratt: Like Dr Welch, Professor Glasziou is also concerned that the downsides of screening have received little acknowledgment.
Paul Glasziou: I think they have definitely been understated. Over-detection is certainly one of the problems. For me that’s a principle reason for not being screened for prostate cancer. If I lived long enough I would end up with prostate cancer. And if I was being screened for it I would eventually have that detected. But it may have never disturbed me in my lifetime. This is particularly true for prostate cancer, but it happens in all cancers.
Alex Barratt: It sounds like we need to change the way we think about cancer.
Paul Glasziou: Yes, breast cancer isn’t one thing. Lung cancer isn’t one thing. Colorectal cancer isn’t one thing. It’s actually a spectrum of diseases. And some of them can be very rapidly fatal. We probably all have known relatives or friends who had a cancer and died fairly quickly after it was detected.
Alex Barratt: Mightn’t it be worth while being screened if screening picks up those aggressive cancers?
Paul Glasziou: Well it turns out that the aggressive cancers are the harder ones to pick up. What we will tend to find in screening is the non-aggressive cancers because they’re around for longer. So it’s easier to find them. Whereas the very aggressive ones appear so rapidly that we’re more likely to miss them.
Alex Barratt: Professor Paul Glasziou is Director of the Centre for Evidence Based Medicine at Oxford. But let’s come back to Rosa. Her screen detected DCIS illustrates the problem that Professor Glasziou and Dr Welch are talking about.
Professor John Forbes is a leading breast cancer surgeon in Australia. He’s the head of the Australian New Zealand Breast Cancer Trials Group and has expertise in DCIS and early breast cancer.
John Forbes: Ductal carcinoma in situ does have various forms and we will become more precise in allocating types of DCIS into high risk for invasive breast cancer and plausibly no risk. But we can’t do that yet.
I do think the term ductal carcinoma in situ is a little outdated. I think a far better term would be a pre-invasive or non-invasive form of breast cancer, to convey to patients that it’s a diagnosis that may increase risk of later breast cancer, but is not in itself a potentially fatal lesion in the breast.
Alex Barratt: So would it be fair to say that it’s only a problem if it goes on to become invasive breast cancer?
John Forbes: It’s a problem in two regards. One is that it may grow to change and become a spreading breast cancer. The other is that it is a marker of risk. One, the risk of a subsequent invasive breast cancer which is a few per cent over five to ten years, which is very much greater than a woman who hasn’t had DCIS. And second, it’s a marker of risk of already having another cancer somewhere else in the breast.
The dilemma that we have in the clinic is that we can make models and we can do statistical analysis and we can conclude with the hypothesis that some of the DCIS is not going to cause a problem. But it doesn’t help the clinician dealing with the individual patient.
Alex Barratt: Because you can’t tell whether it’s one of those sorts of cancers that’s going to cause a problem or not?
John Forbes: Yes, and given that circumstance it’s not surprising that if it was a surgeon, the surgeon would recommend that the lesion be removed. And equally the woman is most unlikely given that single one to one circumstance to say well I’m happy to take my chances.
Karla Kerlikowske: Those particular lesions have a very low mortality. The ten-year mortality rate is about one per cent. No matter how you treat them. Whether you do a mastectomy or a mastectomy and radiation, people tend to survive very well, so most of them probably would not affect a woman’s overall survival at all.
Alex Barratt: Associate Professor Karla Kerlikowske is at the University of California, San Francisco.
Karla Kerlikowske: It’s also true that many people think it’s not just ductal carcinoma in situ but low grade invasive cancers, so there’s probably actually a percentage of low grade invasive cancers that also probably go undetected and not affect a woman’s survival.
Alex Barratt: Karla Kerlikowske has analysed the records of hundreds of thousands of US women who have participated in breast screening over the last 20 years, and has carefully examined the relationship between screening mammography and DCIS.
Karla Kerlikowske: With mammography is that we detect a lot of very low malignant potential lesions and then once they’re identified we see that we have to treat them because we don’t know the natural history.
Alex Barratt: Can you tell me of the breast cancers that are diagnosed by screening what proportion of them are DCIS?
Karla Kerlikowske: It’s about 20 to 25%. The rate goes up with age. If you’re screening women over the age of 70 the likelihood of finding DCIS can be quite high. Someone who is over 70 you know that that is not going to impact their mortality.
Alex Barratt: Right, because I’ve been told that screen detected DCIS is a particular problem in younger women, in women in their 40s and 50s.
Karla Kerlikowske: It’s a problem with having mammography. Prior to mammography in the early 80s the rate of DCIS detection was quite low. Then after the advent of mammography the rate of detection went up five to six hundred percent. And what’s interesting is that has persisted. Some people have suggested that DCIS is a precursor for most invasive cancers. And if we have increased the detection five to sixfold, why haven’t we seen a decrease in invasive cancer? My interpretation of that is that DCIS is not a precursor of most invasive cancers. Because if it was then we should have seen a drop off in invasive cancer. And it’s been 20 years and there’s been no actual decrease. So I think that DCIS might be a precursor of some invasive cancers, and so probably detecting some of them and treating them is preventing some later invasive cancer. But I think more likely it’s a risk factor for a subsequent invasive disease.
Alex Barratt: So a lot of that DCIS represents over detection, picking up cancers that really you’d rather not know about?
Karla Kerlikowske: Correct. I think it’s a risk factor, if we could stop there and just say we’ve detected it and we could think of a medical way to treat it to prevent breast cancer, then I think it would be helpful.
Alex Barratt: Associate Professor Karla Kerlikowske is from the Department of Medicine and Epidemiology and Biostatistics at the University of California, San Francisco.
You’re listening to the Health Report on ABC Radio National, I’m Alex Barratt. This is the first of a three part series investigating cancer screening. In this program we’re looking at one of the downsides of screening that you might not have heard much about – overdetection. At this point you might be thinking I never want to go screening again. Well hold that thought because later in this series we’re going to look at the benefits of cancer screening. And then, how you might go about deciding whether you really want to be screened or not.
For now though, let’s stay with breast cancer and DCIS. If we didn’t screen for breast cancer, most cases of DCIS wouldn’t be found. It’s an example of what we’ve been talking about; the potential of screening to turn up low malignancy lesions that then put you into a quandary about what to do next. So let’s find out, what did Rosa decide to do next?
Rosa: Well he said to me it’s the beginnings of breast cancer and possibly left alone nothing further might happen. However there is a chance that something can come from it. And he said to me, it’s up to you, it’s your choice.
Alex Barratt: How did you feel about that choice?
Rosa: There was no discussion on it. It comes out. You hear the word breast cancer and you think right, okay, I’ll get my things in order. We settled on surgery. I was in overnight. He said it takes four or five days for the pathology to come through. I’ll ring you with the result.
He said I’m not happy with the amount of space I’ve left around the area, could I take some more out? So we booked in for two weeks later and I had some more taken out. That one was worse actually. That surgery was worse than the first one.
Alex Barratt: In what way?
Rosa: Oh because I had to have a drainage tube put in. And I can remember, you know you remember all the good things. I can remember coming out of recovery and they were saying, you know waking me up, you’ve had surgery, are you okay, are you feeling any pain? I said yes, pethidine please! I was almost hysterical. The pain was excruciating.
Alex Barratt: So you didn’t have a whole mastectomy?
Rosa: No, they’ve taken out a golf ball size area. But I’ve been on the Tamoxifen since.
Alex Barratt: And how’s the Tamoxifen?
Rosa: Oh it’s a pain. The hot flushes and the night sweats have been worse than when I was just through the natural menopause. And the mood swings are just like, oh please!
Alex Barratt: So how do you see this whole experience? Do you feel like going for that screening was a good idea?
Rosa: Yes. I looked at it as breast cancer. Not the fact that it was the DCIS and that it might not happen. In my mind we do something about it. And if it was a bit of surgery to get rid of it and get rid of the risk, it’s gone.
Alex Barratt: So you feel this way even though it wasn’t actually cancer, it was pre-cancer. And even though possibly without a screen it would never have been found?
Rosa: Well who’s to know that it would never have been found. I consider myself a breast cancer survivor. In my mind it was going to be breast cancer. And I suppose the mind has a lot to say. I could name you ten women that I know that have had breast cancer. Some have had double mastectomies, about five have died from it. You don’t want to put yourself there.
Alex Barratt: Rosa was happy to have her DCIS found and treated. Maybe the treatment is stopping her getting invasive breast cancer, and maybe it’s saving her life. But then again, maybe it’s all unnecessary.
This problem of deciding what to do with DCIS has been recognised for a while. And so the National Breast Cancer Centre convened a working group to develop guidelines for doctors about how to treat DCIS. Sue Lockwood was the consumer rep on the working party and she wasn’t entirely happy with the outcome.
Sue Lockwood: The guidelines say that it should be treated. Despite my efforts to get options like watchful waiting made available to women and treated very similarly to women with invasive breast cancer. So mastectomy or lumpectomy, followed by radiotherapy. And some of them are being offered Tamoxifen as a means of preventing further DCIS or invasive breast cancer developing.
The one big change is that women are no longer having axillary dissection and are no longer being offered chemotherapy.
Alex Barratt: So, axillary dissection you mean clearance of the lymph nodes.
Sue Lockwood: I do.
Alex Barratt: What were you advocating in the guidelines instead?
Sue Lockwood: I wanted for those women who were comfortable with it, the option of just waiting to see what happens. So that they don’t have to undergo treatment if they don’t actually need to undergo treatment. It’s interesting with invasive breast cancer we started off doing things like radical mastectomies. And over a period of time we were able to roll that back so that women now can have a lumpectomy and radiotherapy and have the same survival outcomes.
I couldn’t see why we couldn’t start to think about that sort of process for DCIS. Why can’t we put in place research programs which look at how we can start to roll back treatment and what sorts of women are most appropriate for rolling back treatment. So why can’t we start with say 70 year olds and say we don’t really need to treat this we think. Would you prefer us just to wait and see what happens and if it develops into invasive breast cancer then we’ll deal with it then. And then gradually move back to say 60 year old women or 50 year old women.
AlexBarratt: And why wasn’t that an acceptable option?
Sue Lockwood: I think because the guidelines working party was dominated by clinicians, and what clinicians want to do is treat, which is fair enough. There has to be a mind-shift somewhere along the way and a lone consumer voice was not enough to change their mind.
Alex Barratt: Sue Lockwood is Chair of the Breast Cancer Action Group in Victoria. As we’ve heard, this issue of detection and treatment of cancers that might not matter occurs in all cancer screening. But perhaps most spectacularly of all in screening for prostate cancer.
Earlier we heard from Noel. Once his urinary tract infection was treated his PSA level came back to normal. But his story doesn’t end there. His biopsy slides were reviewed by a second pathologist who also thought there was cancer. So even though his urinary tract infection was fixed, his PSA was back to normal, Noel still had a cancer diagnosis to deal with.
Noel: Then one urologist convinced me to have the operation. He said you’re so fit you’re so low it will be great. And I said to the other one I think I might have it. And he said well it’s up to you, but what would happen if you found out after the operation you didn’t need it? And I said I’d be very very angry. So he said well it’s possible. And he told me well the prostate movements are normally very slow. So you’re starting from such a low base, why don’t you monitor it every six months or so.
Alex Barratt: So you had treatment options that included surgery or radiotherapy and you’ve decided to do nothing?
Noel: I decided in the end to do nothing yeah.
Alex Barratt: Because of the possibility of side effects from those treatments?
Noel: Yes. No matter what way I looked at it the chances were high enough and I just didn’t want to run that risk if it wasn’t necessary.
Alex Barratt: So this is four years now. In what way do you feel differently? How have you come to terms with it?
Noel: It seemed logical to me what the doctor said. That the movement was slow. I was starting off from such a low base. I would know if I needed it, and we would do it then. And I just felt that was a good way of looking at it. And once I had decided that was the way to do it, having thought about it and studied it, I just live with that. So now I don’t think about it except when I’m about to go in and see him and get the results of the next PSA.
I mean recently I was with a friend and his wife and we were talking and both of them were not in good health, and their daughter was there. And they said Noel how are you? Have you got anything? I said no I’ve got nothing wrong with me except cancer. And the daughter burst out laughing. I hadn’t said it in any kind of funny way, it’s just the truth.
Alex Barratt: We know from research that at least 50% of older men have pathological evidence of prostate cancer if you look hard enough for it. It seems to me that that’s exactly what’s happened in your case.
Noel: Yeah I lived with it because I thought there would be a lot of people living with it, and I could easily have lived with it, never known that I had it, except for that urinary tract infection.
Alex Barratt: So it seems that some men and women are having cancers found by screening and getting treatment for them which maybe they don’t need. Others like Noel may be choosing just to live with their cancers. Well so what. Does that really matter? Dr Gilbert Welch from the US Department of Veterans Affairs.
Gilbert Welch: Well I think there are two problems with being diagnosed with a cancer unnecessarily. First you have the worry associated with the diagnosis of cancer. It is a very serious burden to hear you have cancer. But second, we tend to treat all those cancers. And our treatments have real side effects. All our surgeries have a certain operative mortality associated with them. It’s small but it still exists and it is certainly not a risk you would want to accept if you could benefit nothing from the surgery. But now we often offer considerable additional therapies, both chemotherapy and radiation. And while you would want those therapies if you had a cancer that was destined to progress, you certainly wouldn’t want them for a cancer that really was never going to cause you any problems.
Finding more cancer is not necessarily the goal. Since we now know that there are all these cancers that won’t matter to patients, the standard approach for looking for the test that finds the most cancer is no longer the best test, and we’re sort of really learning this in prostate cancer where we realise virtually half of all elderly men have pathologic evidence of the disease.
But we know it wouldn’t be a good thing to diagnose half the population with prostate cancer and do radical prostatectomies on them. So it becomes a much more challenging question about how to get the right amount of early detection without getting too much.
Alex Barratt: The challenge is to find the cancers that matter rather than finding all the cancers.
Gilbert Welch: That’s absolutely right. The challenge is to find the cancers that matter without dredging up all these other abnormalities that meet the pathologic definition of cancer but would never hurt the patient.
Alex Barratt: So screen detected cancers include a mix of tumours. Some are aggressive, but many are indolent which means the kind of cancer that doesn’t matter. Unfortunately finding them is a side effect of screening.
Next week we’ll look at what might be done to minimise the impact of this major downside. There’s a lot of research going into this, and the answers may involve some important and fundamental changes to the way we think about cancer itself and cancer screening. We’ll also take a look at the benefits; benefits which may have been oversold.
Norman Swan: Alex Barratt made this series and the producer was Brigitte Seega with technical production by Janita Palmer. Alex is an epidemiologist in the School of Public Health at the University of Sydney and in her past life she was actually a journalist.
Reference:
Barratt A et al. Model of outcomes of screening mammography: information to support informed choices. British Medical Journal 2005;330;936
Guests
Dr Gilbert Welch
Professor of Medicine Dartmouth Medical School New Hampshire U.S.A.
Dr Paul Glasziou
Director Centre for Evidence-Based Medicine Oxford University UK
Professor John Forbes
Head of Australian New Zealand Breast Cancer Trials Group John Hunter Hospital Newcastle, New South Wales
Associate Professor Karla Kerlikowske
Dept. of Medicine, Epidemiology and Biostatistics University of California San Francisco
Sue Lockwood
Chair Breast Cancer Action Group Victoria
Further Information
US Preventive Services Taskforce (ratings on the benefits and harms of screening for common cancers)
http://www.ahrq.gov/clinic/cps3dix.htm#cancer
School of Public Health University of Sydney
http://www.health.usyd.edu.au/
Informed health online (Cochrane Consumer Collaboration)
http://www.informedhealthonline.org/item.aspx
National Breast Cancer Centre of Australia
http://www.nbcc.org.au/
BreastScreen Australia
http://www.breastscreen.info.au/
National Cervical Screening Program of Australia
http://www.cervicalscreen.health.gov.au/ncsp/
Prostate Cancer Foundation of Australia
http://www.prostate.org.au/
National Cancer Control Institute of Australia
http://www.ncci.org.au/
The Cancer Council Australia
http://www.cancer.org.au/
Homepage for Dr Gilbert Welch
http://www.vaoutcomes.org/welch.php
‘Should I be tested for cancer? Maybe not and here’s why’ by Dr Gilbert Welch
http://www.ucpress.edu/books/pages/10079.html
Annals of Internal Medicine (contents include many interesting papers on cancer screening, including Dr Welch’s paper on how many women have ductal carcinoma in situ)
http://www.annals.org/content/vol127/issue11/index.shtml
Cancer screening: is it worth it?
http://www.abc.net.au/health/thepulse/s1438910.htm
US National Cancer Institute
http://www.nci.nih.gov/
UK National Screening Committee
http://www.nsc.nhs.uk/
Ottawa Health Research Institute (world leaders in patient decision aids)
http://www.ohri.ca/
Screening and Test Evaluation Program, University of Sydney
http://www.health.usyd.edu.au/
Cancer Screening: Benefits and Harms, Part Two of Three (Repeat)
Listen Now – 27022006 | Download Audio – 27022006
Part two of this series looks at what might be done to minimise the impact of the downside of screening.
The series is presented by Dr Alex Barratt, Associate Professor of Epidemiology at the University of Sydney.
This program was first broadcast on 29th August, 2005.
Show transcript | Hide Transcript
Transcript
This transcript was typed from a recording of the program. The ABC cannot guarantee its complete accuracy because of the possibility of mishearing and occasional difficulty in identifying speakers.
Norman Swan: Welcome to the program.
This morning on The Health Report, the second in an important and controversial series which seriously undermines the notion that finding things early is always best.
Health people are screened for all sorts of things – but particularly the most terrifying disease of all: cancer – whether it be of the breast, cervix, bowel or prostate.
These programs, made by Associate Professor Alex Barratt of the School of Public Health at the University of Sydney, suggest that deciding to be screened for cancer is not a trivial decision and needs careful thought because it can mean you’re forced onto a medical and surgical merry go round you were never meant to be on.
We all need to think twice about this. Alex is a physician and epidemiologist specialising in this field.
Alex Barratt: Last week we talked about why you might choose not to be screened. The number one reason is the risk of finding a cancer that doesn’t matter. The startling idea that you might find a cancer you’d rather not know about. In this week’s program some more on the downsides of cancer screening, and then the good news, the benefits.
As you heard in the first program, looking for cancer can turn up cancers that don’t matter. In fact the more you look for cancer the more you find. And this can lead to unnecessary treatment. Now let’s go back to Noel.
Noel was in his mid 50s when he had prostate cancer found, almost by accident. He had a urinary tract infection which caused a raised PSA. That’s Prostate Specific Antigen, which lead to a biopsy which showed he had cancer. After his urinary tract infection was treated his PSA went right down to normal. But he and his doctors were left in a quandary about what treatment, if any, Noel should have for his cancer. His options included surgery to remove his prostate – a radical prostatectomy.
Noel: One urologist convinced me to have the operation. And the other one said well it’s up to you, but what would happen if you found out after the operation you didn’t need it? And I said I’d be very very angry. So he said well it’s possible. And he told me well, you’re starting from such a low base, why don’t you monitor it, and I just felt that was a good way of looking at it. Now I don’t think about it except when I’m about to go in and see him and get the results of the next PSA.
Alex Barratt: Four years later it’s still very low, around one, when abnormal levels are four or more. Because some screen-detected cancers don’t progress, like Noel’s, one way of dealing with them is just to monitor them.
Surprisingly perhaps the same approach of watchful waiting has been suggested for one of the deadliest cancers of all, lung cancer. Dr Gil Welch is a physician with the US Department of Veterans Affairs and Professor of Medicine at Dartmouth Medical School.
Gilbert Welch: There are so many abnormalities in the lung, even the proponents of screening don’t want to act on every abnormality found. And so they are following small abnormalities to try to figure out which ones are growing. Now this is a very new idea for patients and physicians. What you do is say ha, here is an abnormality, let’s see what happens to it over the next three, six months. This is a paradigm that is relevant probably for all cancer testing.
To be fair that may be a very difficult emotional burden for patients. We’re going to say the best thing to do is not to act on it. And it would help a lot if we didn’t call it cancer. Some patients may say, I want to do that. I understand probably the best way to get the most out of screening without getting hurt is to accept that early abnormalities are going to be followed. And others may say I want no piece of this. I want to live my life, focus on being healthy, and not getting medicalised before I feel ill. And I think either choice is rational.
Alex Barratt: Dr Gil Welch. As you heard, monitoring screen-detected abnormalities – rather than rushing in to treat them – is an approach that could be applied across all cancer screening. In fact in Australia we’re right in the middle of this logic being applied to cervical cancer screening.
Low grade changes in the uterine cervix are caused by infection with the human papilloma virus. Infection with HPV is very common. So common that it’s called the common cold of the cervix.
In almost all cases the virus is cleared by the immune system. But if infection persists over a long time, say 10 or 15 years, it can develop into cervical cancer. So low grade changes are not cancer, they’re nowhere near cancer. But nevertheless they’re abnormalities found by cancer screening. They cause a lot of anxiety, and women with these low grade changes on their pap smear tend to be referred for an examination of the cervix (called colposcopy) and perhaps biopsy or even treatment, including removal or destruction of part of the cervix.
But under new guidelines that will change. Professor Ian Hammond is chair of the committee overseeing this policy change.
Ian Hammond: Women who get a low grade pap smear report should have a repeat pap smear in 12 months. And if in 12 months time everything has gone away, that’s terrific. But if it’s still there in 12 months time the low grade change, then they should be sent for a colposcopy. About 50% or more would be negative a year later. And that means that half of the women that were going to be referred for colposcopy won’t need to be.
We’re talking here about mainly young women. If you take women to age 25, 25% will have a low grade change on a pap smear. That’s an enormous number of women. It creates a big burden for the medical systems, and also great anxiety for those women.
Alex Barratt: But it does mean that women are going to have to wait for 12 months or so to have this issue resolved. Do you think that’s going to be difficult?
Ian Hammond: This is all to do with education. And not just the public. I think the doctors find this very difficult. Because now we’re saying most of the low grade change never ever goes anywhere near being a cancer. And in fact in many countries they don’t do pap smears in women under 25 or under 30. Yet we’re not seeing an increased number of cancers in those countries, in fact we’re seeing just the same rate of cancer in those countries as we see here. And all it means is we’re detecting women who are destined to get better on their own.
Alex Barratt: So what you’re saying is there’s really been a massive over-detection and over-treatment in our cervical screening sytem here?
Ian Hammond: That’s absolutely right. If you take just two countries, just take Finland and Australia, we have exactly the same, almost the same rate of incidence of cervical cancer and we have the same rate of mortality in cervical cancer. We treat ten times more people, destroy part of the cervix, than they do in Finland.
Alex Barratt: But no matter how reasonable and rational it might be just monitoring screen-detected abnormalities could be really emotionally tough on patients. The stakes are of course even higher when what’s being monitored is actually cancer, rather than just a minor abnormality such as we’ve just been hearing about in cervical cancer screening.
Although watchful waiting is used in the management of prostate cancer there are no trials of the effect of treatment versus watchful waiting in men with screen-detected prostate cancer. Especially when cancers are found in relatively young people, choosing between treatment or watchful waiting can be a very emotional issue. Some would say with even higher stakes. In these cases maybe watchful waiting just isn’t a good enough solution. If we could study the actual cancer itself to find out how individual cancers behave, maybe we could use that knowledge to make treatment decisions.
Professor Pamela Russell is a cancer biologist. She explains how it is that some cell changes, and even cancers, can stay the same or go away.
Pam Russell: There are growth factors which regulate the growth of cells and then there are inhibitors to turn that off if that goes wrong. There’s a gene called p53 which has the ability to tell the cell to stop in division if it senses there’s something wrong. If the cell can’t be fixed then another pathway which also involves p53 tells the cell to die, and that’s going on all the time.
Alex Barratt: It’s not inevitable that it will progress down this spectrum to cancer?
Pam Russell: No it isn’t. The other part that I haven’t mentioned is the immune system, and there’s certainly surveillance which knocks out cells which are abnormal. I think we need markers which are going to tell us, is it going to be a bad tumour or is it going to be a good tumour. And there’s a huge search on for those markers.
Recently the Cancer Institute has given a consortium of people, of which I am one, a grant to look particularly for markers in prostate cancer and can we use it to say this patient’s going to require aggressive treatment and this patient can be left alone.
Alex Barratt: Professor Pamela Russell is the head of the Oncology Research Centre at the Prince of Wales Hospital in Sydney.
But we don’t have these markers yet, so for now cancer screening still brings significant risks of over-detection and over-treatment. But there are other downsides too.
Let’s meet Alistair. He decided to have a PSA test as a sort of birthday present to himself when he turned 40. He went to see his GP and a test was arranged at a local path lab. They said they’d call when the results were ready.
Alistair: I sort of had forgotten about it. The appointment was on the Tuesday, and Thursday afternoon I got a phone call from the doctor’s receptionist saying oh we need to make an appointment, she needs to talk to you. The earliest appointment we could get was on the Monday afternoon. That didn’t make for a very good weekend I have to say. I did ask the receptionist if I could be told what I needed to be told over the phone, and the receptionist said no I had to speak to the doctor in person.
Alex Barratt: You said it was a lousy weekend. Compared to other anxious moments in your life, how did this one rate?
Alistair: I suppose I was beginning to look at my own mortality in some respects. And I was angry that I wasn’t in control of what could be a potentially life-threatening situation. And unfortunately I suppose I took it out on the ones I loved in a way. I was just very short – I was frightened I suppose.
Come the Monday when the appointment came about I dragged my wife along with me, because I’m a pretty lousy person with bad news. So we went in and the doctor chatted and I’m on complete tenderhooks. And it turns out that I had slightly raised cholesterol and my PSA level was non-existent. So I gave her an earful I have to say. She’d completely forgotten that part of the blood test was a PSA and completely understood my nerves.
Alex Barratt: All that and Alistair didn’t even have an abnormal test. But lots of people do. Dr Welch again.
Gilbert Welch: The basic issue is that cancer tests can be wrong. They may suggest you have a cancer when in fact you do not. And while doctors sort this out patients go through an increasingly invasive testing and experience what is often described as the scariest time of their life.
Alex Barratt: That’s a very distressing situation. But how often does that happen?
Gilbert Welch: Actually it’s a lot more common than is commonly thought. The typical cancer screening test, somewhere in the order of 5 to 10% of people will experience a false positive, that is a cancer scare. They don’t really have cancer but the test is abnormal. Now 5 or 10% may not sound like a lot, but it cumulates if you have repeated testing. And so it’s been estimated that 10 year course of annual mammograms the expectation of you having at least one abnormal in the course of that 10 years approaches 50%. So it is actually quite common.
If you do all these cancer tests over many years the chances are very high that at one point you will have to worry about whether or not you have the disease. And there is a subset of patients that keep getting worrisome results, they keep being told to come back for subsequent testing. They never quite get a normal test. And that can be really quite exhausting and demoralising.
Alex Barratt: Can you give me an example of that?
Gilbert Welch: When I was seeing a patient and was offering him a PSA test and I was describing this downside that a lot of men had abnormal PSA’s and had to go through a number of tests before they could really sort out whether in fact they had cancer or not. And his wife immediately chimed in, “boy that’s a lot like cervical cancer”. And she then recounted this story where she had had an abnormal pap smear and it kept being abnormal. And then she had a cone biopsy of her cervix and her pap smear remained abnormal. She had her cervix frozen. It was never showing cancer but it was never saying it was healthy either. And ultimately some of the doctors suggested that she should have a hysterectomy. And she really felt like she was in a quandary.
Alex Barratt: What we’ve been talking about so far are false alarms. But the opposite can happen too. Screening can miss cancers and cancers can occur between screenings. These are called ‘interval’ cancers because they’re found in the time interval between screens. In breast cancer screening for example, even among women who are screened regularly, 20 to 30% of the cancers diagnosed in those women are not found by screening, they’re interval cancers. And despite telling women that screening doesn’t find all cancers it can still come as a rude shock when a woman who is regularly screened gets one of these interval cancers.
Professor Mark Elwood is the Director of Australia’s National Cancer Control Initiative, an organisation that advises the Australian government on cancer control.
Mark Elwood: People would like to think that well if they have this test it will detect anything and therefore if they have this test and it is negative it means that they are safe. I think a lot of people have tried very hard to get that message across, that that’s not the case. Screening does not detect all disease.
Alex Barratt: I doubt that people would realise that it misses 20 to 30%.
Mark Elwood: I think that’s pretty good. I mean if you tell me that a screening test has a 70% chance of detecting a disease when it is so early that no other test can detect it. To me I think that’s pretty good. I mean for colorectal disease it’s less, it’s probably 50 to 60%. I’m aware of that, but I still think it’s a good idea.
Alex Barratt: Professor Mark Elwood. And more on bowel cancer screening later.
This is The Health Report on ABC Radio National. I’m Alex Barratt.
Alex Barratt: So these are the main downsides of cancer screening. First over-detection and over-treatment, then cancer scares, what we call the false alarms. And finally interval cancers or false negatives. But we need to weigh these downsides against the benefits. So what are they?
Well the main one of course is the chance of finding an aggressive cancer early, and so treating it more effectively. Here’s David Sandoe, co-chair of the Support and Advocacy Committee of the Prostate Cancer Foundation of Australia. After him you’ll hear Dorothy, who had a breast cancer found by screening.
David Sandoe: I was diagnosed in a normal executive medical check and I went through the various options. And because of early detection I believe that I’ve got a fair chance now of not having prostate cancer. And I encourage all men aged 50 to have a PSA test, a blood test and a digital examination, because early detection is key.
Dorothy: I was diagnosed with breast cancer in ’97. I had a lumpectomy done and I was on Tamoxifen for five years, and I had a bad side effect from the Tamoxifen. It was mainly the hot flushes. And I’d never had any lymph nodes taken away or anything like that. So I was very lucky.
Alex Barratt: Dorothy and David may well be right, that early detection has cured their disease. But, uncomfortably, it could also be that it made no difference. Because it is impossible to be sure for any individual what the outcome would have been without screening we rely on randomised trials to demonstrate whether there really are benefits or not. Dr Welch again.
Gilbert Welch: No screening test is better studied than mammography. Over half million women have been entered into randomised trials of the technology. And yet there’s still a debate. And I think that’s really important for people to know that even though we devoted a lot of resources to try and figure out how this test works, there’s still debate about whether it works. And that’s not something I think peculiar to mammography, I think it really speaks to just how difficult it is to study screening tests. The reason it is difficult to study it is because the effects are small.
So for example the very first study of mammography, the health insurance plan of New York about 30,000 women received mammograms and the physical exam about 30,000 did not, were the control group. And the findings of that trial were really quite dramatic. The death rate from breast cancer was about a third lower in the screened group. 147 women died of breast cancer in the screened group and 192 died of breast cancer in the control group.
Alex Barratt: So 45 deaths prevented by screening 30,000 women.
Gilbert Welch: That’s correct.
Alex Barratt: It’s sounding to me like there is quite a big benefit there.
Gilbert Welch: Well, of those 30,000 women, 29,965 did not benefit from screening. This is the general principle of screening. You’re dealing with people who are fundamentally at lower risk, most of whom will never experience the outcome that you’re seeking and seeking to change. And so you have to involve many people to potentially benefit a few. That may not be a reason not to do it but it is certainly one reason to be cautious before charging ahead. But the ones who do benefit, benefit big. And that is really why I say it’s a two-edged sword and I’d say our best guess in any screening test is that there are some people who will benefit. There will be a large number of people that stand nothing to gain. And some of them will be harmed.
And one other thing I want to be clear about, most of the other tests, and in fact all the other tests beside colorectal cancer screening really have not been studied. And so there’s a lot of strong belief out there. Unfortunately that belief is not always supported by the data.
Alex Barratt: Let’s stay with mammography for a little longer, because we have more trial data on this than on any other screening test. Professor Paul Glasziou, Director of the Centre for Evidence Based Medicine at Oxford University agrees that mammography is still controversial. One reason is a review of the evidence by the prestigious Cochrane Collaboration. That’s an international group which regularly reviews evidence about a range of health care interventions.
This particular review reignited a ferocious debate about whether the mammography trials really show any benefit at all.
Paul Glasziou: There’s been some controversy because of the Cochrane Review. There were some problems identified with the quality of the data of the various trials that the Cochrane Review has correctly identified. But let’s just put that to one side. If we accepted the evidence that there is a reduction in breast cancer mortality from screening, then we’re talking of the order about a one-third reduction. That’s best proven in the age groups from 50 to 70, and there’s been controversy about those under 50 and those older, over 70.
If we look at the under 50s there are two problems here. One is that instead of a one-third reduction we’re getting something substantially less than a one-third reduction. And there’s some plausible reasons for that. It’s harder for the mammograms to detect cancers in that age group and there’s also a different mix of cancers in that age group, so there may be more aggressive cancers.
The second problem though is that breast cancer is actually much rarer in women under 50. So not only is the relative effect less but also the absolute effect, the numbers per ten thousand is much less. So for two reasons we’re actually getting less impact in that particular age group. But with all of the attendant harms that we’ve discussed previously such as the over-detection, the over-treatment and the false positives.
With the over 70s there’s also been controversy because the cancers are more frequent in that age group, but older people are more likely to die of something else, and you get an increase in the over-detection problem. You’ll get cancers that weren’t going to disturb people in their lifetime being detected. So there’s an increased downside in that older age group as well.
Alex Barratt: Professor Paul Glasziou from Oxford University.
Randomised trials have also found a benefit for bowel cancer screening. Screening reduces the risk of death from bowel cancer by 30 to 40% in people who are regularly screened over 5 to 10 years. There are plans for a national bowel screening program to begin here in Australia. Professor Mark Elwood worked on pilot projects to see how it might be done.
Mark Elwood: In some ways it’s the simplest possible cancer screening test, because to do a fecal occult blood test you do the test at home. It’s basically a test where you need to take a very small amount of fecal material, bowel motion, which you do with a thing like a blunt needle. Then that blunt needle goes into a tiny little test tube, and then you wrap the test tube up in the packaging provided and post it off to the laboratory. If the test shows that there is in fact blood in the bowel motions, the next level of investigation is a colonoscopy which is normally done by a gastroenterologist or a surgeon. So that’s really the demanding step in terms of specialist availability.
Now in Australia according to the specialists in those areas we think we can manage that. But New Zealand for example has decided a few years ago not to go ahead with the screening program. And as far as I know that decision was primarily on the basis of the lack of specialist medical availability to do the follow-up tests.
We are one of the very few countries which is moving in this direction. The UK has got a commitment to a program, Norway and maybe one or two other European countries are very gradually introducing programs. So we’re actually up there with the world leaders.
Alex Barratt: Professor Mark Elwood is Director of the National Cancer Control Initiative. Although a large-scale government funded program of bowel cancer screening is only in its early stages, bowel cancer screening has been available through Medicare for some time, either by fecal occult blood tests as Professor Elwood described, or by colonoscopy. And that’s what Carole had.
Carole: Well I went and had a colonoscopy. That showed that I had a tumour and it would mean surgery to have it removed. In two weeks later I had the surgery, and then when they removed the tumour they can then tell you the results and it was what they say is a Dukes B, so I was lucky it only spread to the second lining and there was no spread to the lymph nodes in my pelvis or any other organs. So I was extremely lucky. Had I waited for symptoms I would probably have been in a very difficult situation. Because in my case it hadn’t spread so I didn’t have to have chemotherapy, which was a blessing. Whereas if it was found too late, waiting for symptoms, then I probably would have had to have chemotherapy and been a lot iller than I was.
Alex Barratt: Carole was only 41 when she was screened. That’s young for bowel cancer screening. But she had a really good reason to go for that colonoscopy.
Carole: My nana had seven primary cancers and they started I think in her early 50s and she survived to about 73. But with cancers keep reoccurring and they were all different ones, not spreads. And my mother started at a similar age. So therefore it sparked an interest at the hospitals and they found that we have a really rare hereditary cancer gene. And if you look at the family tree of other members, aunties and uncles and sisters and brothers of my nana it shows a real pattern of cancer, and suggested that my brother and myself get screened regularly, which is what we’ve been involved with. I think it’s a good thing because if you know you’re forewarned, you’re forearmed.
In our family case the cancer screening is probably a lifesaver, and I probably would not be sitting here now talking to you if I hadn’t had it.
Alex Barratt: Carole comes from a family with a very high risk of cancer, because of a rare cancer gene. So it makes sense for her to be screened, and indeed to start testing younger than people with an average risk. Following this line of thought I asked Dr Welch, who’s most likely to benefit from cancer screening?
Gilbert Welch: That’s really people who are extraordinarily high risk of dying from cancer because of a very strong family history for example, or something in their genetic makeup, people for whom cancer is the major source of expected mortality. And these are the people who should most carefully consider undergoing regular screening.
Alex Barratt: Professor John Forbes is a breast surgeon who’s been involved in some of the world’s biggest trials of breast cancer treatment. He agrees with Dr Welch’s approach and argues we could go even further by matching a woman’s individual breast cancer risk to her screening strategy. Professor Forbes.
John Forbes: I’ve long thought that our model is a little rigid. The model is a two yearly screen and it’s the same program fits all. But we do have good, simple, cheap tools for clarifying a woman’s risk. One of the most important is breast density. If we reviewed the current model and just used breast density as an example of risk assessment we might be able to achieve something like a third of the women or less having an annual screen, and two-thirds of the women or more having perhaps a three yearly screen. Plausibly cost neutral, but less morbidity and a more effective tool in the sense that the women would be at higher risk. And there really are a handful of other things that can be put into risk models. They take about 30 seconds to a minute to complete and you can allocate a risk category to a woman.
And then leaving aside the very high risk and leaving us with perhaps 80% or more of the population, can we allocate that very large group of women into lower and higher risk and have a different screening model for them. And I believe that this is something that should be explored today.
Alex Barratt: John Forbes is Professor of Surgical Oncology at the University of Newcastle and the Newcastle Mater Hospital.
So deciding what to do about cancer screening is complex. It involves balancing the benefits against the harms. Whether there’s a net harm or a net benefit varies, depending on which cancer you’re talking about, the level of cancer risk, which test or tests you use, and how often you screen.
You can see this approach in action on the website of the US Preventive Services Taskforce. Their very influential recommendations rate screening on a scale from A to D. An A recommendation is strongly in favour of screening, because there’s good evidence that benefits substantially outweigh harms. Cervical cancer screening by pap smears, and bowel cancer screening both get A ratings.
Breast cancer screening by mammography has a B rating. It’s a recommendation in favour of screening, but indicating fair, rather than good evidence that benefits outweigh harms.
At the opposite end there’s a D rating. That’s a recommendation against screening. Because there’s evidence that harms outweigh benefits. Testicular cancer screening and ovarian cancer screening both have D ratings.
Some things like screening for prostate cancer get an I rating. That’s I for insufficient evidence for a recommendation either for or against.
We’ll put the link to their site on the Health Report website.
So how do you make sense of all this? Unfortunately there’s one more factor you should be aware of. Next week we’ll look at the forces driving cancer screening. Some of them might surprise you. We’ll also look at some new and interesting ideas about how you might make your own decision about which cancers if any you want to be screened for.
Norman Swan: Alex Barratt made this series and the producer was Brigitte Seega with technical production by Janita Palmer. Alex is an epidemiologist in the School of Public Health at the University of Sydney.
Further Information
School of Public Health University of Sydney
http://www.health.usyd.edu.au/
Screening and Test Evaluation Program, University of Sydney
http://www.health.usyd.edu.au/
National Breast Cancer Centre of Australia
http://www.nbcc.org.au/
BreastScreen Australia
http://www.breastscreen.info.au/
National Cervical Screening Program of Australia
http://www.cervicalscreen.health.gov.au/ncsp/
Prostate Cancer Foundation of Australia
http://www.prostate.org.au/
National Cancer Control Institute of Australia
http://www.ncci.org.au/
The Cancer Council Australia
http://www.cancer.org.au/
US Preventive Services Taskforce (ratings on the benefits and harms of screening for common cancers)
http://www.ahrq.gov/clinic/cps3dix.htm#cancer
Informed health online (Cochrane Consumer Collaboration)
http://www.informedhealthonline.org/item.aspx
Homepage for Dr Gilbert Welch
http://www.vaoutcomes.org/welch.php
‘Should I be tested for cancer? Maybe not and here’s why’ by Dr Gilbert Welch
http://www.ucpress.edu/books/pages/10079.html
Annals of Internal Medicine (contents include many interesting papers on cancer screening, including Dr Welch’s paper on how many women have ductal carcinoma in situ)
http://www.annals.org/content/vol127/issue11/index.shtml
US National Cancer Institute
http://www.nci.nih.gov/
UK National Screening Committee
http://www.nsc.nhs.uk/
Barratt et al. Paper on outcomes of mammography screening in Australian women
http://bmj.bmjjournals.com/cgi/content/full/330/7497/936
Barratt et al. Users Guide to the Medical Literature: XVII How to use guidelines and recommendations about screening
http://jama.ama-assn.org/cgi/search?fulltext=Barratt+AL&submit.x=4&submit.y=11
Informed health online (Cochrane Consumer Collaboration)
http://www.informedhealthonline.org/item.aspx
A decision aid on HRT for Australian women. Developed by the Sydney Health Decision Group for the NHMRC
http://www.nhmrc.gov.au/publications/synopses/wh35syn.htm
Cancer screening: is it worth it?
http://www.abc.net.au/health/thepulse/s1438910.htm
Ottawa Health Research Institute (world leaders in patient decision aids)
http://www.ohri.ca/
Guests
Professor Ian Hammond
Clinical Professor Director of Gynaecology King Edward Memorial Hospital for Women Perth, Western Australia
Dr Gilbert Welch
Professor of Medicine Dartmouth Medical School New Hampshire U.S.A.
Dr Paul Glasziou
Director Centre for Evidence-Based Medicine Oxford University UK
Professor John Forbes
Head of Australian New Zealand Breast Cancer Trials Group John Hunter Hospital Newcastle, New South Wales
Professor Mark Elwood
Director Australian national Cancer Control Initiative
David Sandoe
Co-Chair Support and Advocacy Committee Prostate Cancer Foundation of Australia
Professor Pamela Russell
Head Oncology Research Centre Prince of Wales Hospital Sydney
6 March 2006
Cancer Screening, Benefits and Harms – Part Three (Repeat)
Listen Now – 06032006 | Download Audio – 06032006
The final part of this series looks at forces driving cancer screening and at some new and interesting ideas about how people might make their own decision about which cancers, if any, they want to be screened for.
The series is presented by Dr Alex Barratt, Associate Professor of Epidemiology at the University of Sydney.
This program was first broadcast on 5th September, 2005.
Show transcript | Hide Transcript
Transcript
This transcript was typed from a recording of the program. The ABC cannot guarantee its complete accuracy because of the possibility of mishearing and occasional difficulty in identifying speakers.
Norman Swan: Welcome to the Health Report.
This morning on the programme, the last in our series on cancer screening, which has been made by Associate Professor Alex Barratt of the University of Sydney’s School of Public Health.
Now with a job like that you’d think Alex would have been telling you how important it is to detect cancer early and have it treated.
Well, not quite. The series so far has revealed that when you’re healthy and have no signs that anything’s wrong, going off for a cancer test can do more harm than good.
So, how on earth do you decide? Well, that in part is what today’s programme is about.
Montage:
I think every woman should have a mammogram done. I’m very much in favour of the mammograms.
And I encourage all men aged 50 to have a PSA test and a digital examination because early detection is key.
I suppose I was beginning to look at my own mortality in some respect and I was frightened I suppose.
I could name you 10 women that I know who had breast cancer and some had had double mastectomies, about 5 have died from it. You don’t want to put yourself there. It’s scary that it’s so common. It’s very scary.
Gilbert Welch: Well I think one of the things to do is to try to take a deep breath and relax. It feels like it’s an incredibly weighty decision, that you can make a huge mistake.
But I think actually it’s hard to go too far wrong. The chance that you will benefit is quite small, so is the chance that you will be harmed is relatively small as well.
Alex Barratt: Dr Gil Welch, a physician with the US Department of Veterans Affairs.
Today we’re going to look at how you might make your own decision about which cancers, if any, you want to be screened for. Before that though let’s take a look at the forces that drive cancer screening. As we’ve seen over the last two weeks, cancer screening has some pretty big downsides. Yet almost everyone’s strongly in favour of it. So the question is why there’s so much public and professional enthusiasm for it.
Gilbert Welch: There’s no single answer to that question. I think there are a number of explanations. Just the idea of early cancer detection is just so appealing. People are very genuinely scared by cancer and there’s a widespread belief that gee there’s no reason not to look for cancer early, and there’s every reason to look for it early.
And this is part of a broader culture that uncritically accepts medical testing is a good thing, without recognising that testing does have downsides, that it does find things that otherwise wouldn’t bother you, and that it can start a chain of events that’s very difficult to stop.
Now I’d like to add a couple of other drivers, and it would not be correct not to bring up the topic of money. There are strong incentives. One of them is obviously for the test manufacturer or for the physicians that interpret them, whether they’re mammographers or radiologists, they’re good business right. Because they involve a lot of people, so they’re big markets.
It’s also become in the interests of medical centres to find cancer early. I’d like to read a quote by Otis Brawley, a urologist who went on to be a director of the Georgia Cancer Centre and worked at Emory University. He wrote that ‘We at Emory had figured out that if we screen a thousand men at the North Lake Mall this coming Saturday we could bill Medicare and insurance companies for about 4.9 million dollars in health care costs’.
But he goes on to write that the real money comes later from the medical care that the wife will get in the next three years because Emory cares about her man, and from the money we’ll get when he comes to Emory’s emergency room when he gets chest pain. I think there’s a lot of interest in garnishing patients, and one way to get patients is to offer free screenings.
Alex Barratt: Dr Gil Welch. One current example of a significant commercial opportunity is the test for human papilloma virus, the virus that causes cervical cancer. Not surprisingly the test is being strongly promoted by its makers, Digene who think it should be incorporated into cervical cancer screening because they argue it’s good for women. But there’s a lot of dispute about whether it would actually add anything to screening other than a lot of anxiety and cost.
Dr Angela Raffle is a world leader in research on cervical cancer screening, and she’s had a close look at what Digene’s been up to in promoting the HPV test.
Angela Raffle: The British medical Journal carried an article saying that perhaps we should solve all the problems in cervical screening by using HPV testing. And our newspapers are full of photographs of very well known celebrity women who apparently were campaigning for all 15 European nation states to introduce HPV testing into the cervical screening program right away, Carol Smiley, Honour Blackman, Jilly Cooper. I think they would be the most prominent.
Well fortunately a very astute investigation of a journalist spotted that something strange seemed to be happening. And he contacted all the celebrities who were named on the website for the group. None of them knew that they had anything to do with the campaign. He managed to track down who’d set up the campaign which wasn’t easy because it all traced back to a PO Box in Brussels. Nobody was allowed to divulge who’d set it up. But it turned out to be Burson-Marsteller which is a big PR company who were working on behalf of Digene, and they’d completely manufactured the whole celebrity group.
Alex Barratt: And they had done it to put pressure on governments in Europe and the UK, to include HPV testing as part of the screening program?
Angela Raffle: They’d done it precisely for that. And it creates the impression that oh well HPV testing must be a good thing because all these very high profile women must have independently looked at the evidence and made their minds up.
Alex Barratt: Dr Angela Raffle runs the NHS Breast and Cervical Cancer Screening Programs in Bristol, England.
Research in the prestigious journal of the National Cancer Institute found that 70% of US women and 60% of men had seen celebrity endorsements in the past year. About a quarter said the endorsements made them more likely to be screened.
In the UK doctors get paid more if they screen more people with approved screening tests including pap smears. Likewise here in Australia family doctors are eligible for additional government payments if they reach target levels of women in their practice having regular pap smears. In fact many people believe that doctors should be aiming to screen as high a proportion of the eligible population as possible. But there might be some major problems with this line of argument. Dr Welch.
Gilbert Welch: You know we really want to measure medicine now. And well where are we going to start? As from following heart attack, that’s one. Any screening test. That’s another. And that became part of our health care report cards. We had to do some fighting to try and get some of this stuff off. The 100% that’s not a good goal, scaring people. I mean you got to do this. Doctors we like to do well. So if we’re being measured and if we keep getting a reminder telling us that this woman needs to be screened, we are going to do our best to make sure she does. I think most physicians in practice feel that we can only be penalised by failing to test.
Alex Barratt: Dr Gil Welch, a Physician with the U.S. Department of Veterans Affairs.
The trouble is that if health care providers who deliver screening are trying to screen as many people as possible, that’s in direct conflict with the need to inform patients about the potential harms of screening. Like Dr Welch, Professor Paul Glasziou, Director of the Centre for Evidence Based Medicine in Oxford is uncomfortable with the notion of getting as many people through the door as possible.
Paul Glasziou: I think we have to realise that the ethics in screening are different to the ethics of treatment. But I think we’ve come to it with a treatment mentality, that is, the usual doctor-patient relationship of saying well this is the treatment that I think you should have and the sort of minimally informed consent process. Whereas the standard should actually be higher for screening because we’re going out to basically well people and saying we think you should have this particular screening done because we think it is a good idea, without really asking them whether they think it is a good idea. We’ve done it from our perspective. And part of the problem as I see it is the lack of understanding by health care workers providers in general, so that the people making some of these decisions don’t understand the complex issues of screening. I certainly didn’t learn about them going through medical school. And I think that’s the area where we need further education for them to understand that these are complex issues. That there are downsides, that it’s not a straightforward case and that we need consumer involvement as well.
Alex Barratt: Professor Paul Glasziou is from Oxford University. Later we’ll come back to how you might get more involved in decisions about your own screening.
For now though let’s stay with this drive to get as many people screened as possible. Another argument for it is an economic one. How much does screening cost, and just how cost-effective is it? Associate Professor of health economics, Glenn Salkeld from the University of Sydney explains, using bowel cancer screening as an example.
Glenn Salkeld: Bowel cancer screening I guess doesn’t come cheaply. It would cost us more than $100 million a year to run this program and that’s over and above what we currently spend on detecting and treating bowel cancer. So depending on the number of people we end up screening it costs anywhere from 100 to 200 million dollars a year.
Alex Barratt: So the bottom line is that it costs money. It doesn’t actually save money overall?
Glenn Salkeld: It doesn’t save money overall, no. You’re spending money to save lives. That’s what it comes down to. And so I don’t think anyone looks at screening as a magic panacea to save the health budget. We spend more than $50 billion a year on health care. And we have to ask two questions for any health care program, be it screening or whatever. Does it work and what does it cost. And if you can measure those two things, put them together and what you get is this ratio of cost to effect or cost effectiveness. So it really tells us are we getting value for money. And when it comes to the bowel cancer screening the answer is pretty unambiguous, it’s yes we are.
It’s about 22 to 24 thousand dollars per life year saved. So that means that we have to spend about $24,000 to save one extra year of life.
Alex Barratt: And how does that compare with other cancer screening programs?
Glenn Salkeld: Well breast cancer probably comes in just below $20,000 per life year saved and cervical cancer screening would be somewhere in the mid 30’s.
Alex Barratt: So it’s not the total cost, but rather what you’re getting for your money that matters. And there is this notion around that you need economies of scale to get maximal cost-effectiveness from your screening program. The breast and cervical cancer screening programs in Australia have participation targets, such as 70% participation in two yearly mammograms amongst women aged 50 to 69 years. This sounds a bit of a technical argument, but it is important because it’s another driver of trying to get people through the door of screening services.
Glenn Salkeld argues that the economy of scale argument might be wrong, and that getting more people doesn’t make screening more cost effective.
Glenn Salkeld: It’s a simple equation. If you have half the people coming you end up with half the cost roughly and half the benefit. So when we talk about a cost effectiveness ratio. The ratio in effect stays the same. So you’re still going to be around the 20,000 per life year saved. I think what a lot of screening programs do is set the figure at 70% but we don’t know why. I think the key thing here is that even if we don’t achieve 70 to 80% of participation rate, even if we get to 40% or thereabouts it’s still cost effective.
Alex Barratt: Associate Professor Glenn Salkeld. So the bottom line is that maybe we don’t need to recruit as many people as possible to screening. Especially as trying to do that puts screening programs in a difficult situation when it comes to telling you about the downsides.
This problem has been recognised in the UK and there the national screening committee decided to move away from trying to maximising participation. Instead they now focus on making sure people know what they’re getting into before they have a screening test. They call it informed choice. The committee’s program director is Dr Muir Gray.
Muir Gray: The decision we made about five years ago was that we were to move a decision, public health decisions away from our utilitarian base where we thought of the greatest good for the greatest number. But to make sure that individuals would make a choice in which they knew the benefit and the harm, the probability of both, and they could make a choice based on their values. So informed choices, a choice that is informed by best current evidence and given in a way that allows the individual to relate it to their condition and their values.
Alex Barratt: So people might make different decisions about whether to be screened for cancer or not.
Muir Gray: Yeah, it’s the evidence is the evidence, but every decision is different, depending on the condition of the individual other risk factors etc and when they’ve weighed up the implications of evidence for them as an individual. It’s their values that have to be paramount.
Alex Barratt: So if we now start telling people about the downsides, might fewer people go along to be screened? Dr Gray again.
Muir Gray: We haven’t seen a marked drop so far, but we decided that was a price worth paying and we were prepared to accept the fact that a lower proportion of women might accept the offer of screening.
Studies in PSA testing show that if people are better informed a smaller proportion take up the test. That’s what I would call a good thing, but that’s my values coming in. I think in the whole of medicine and health care we need to think a lot more about how we present information. So I think we see for the future offering people a wide range of different decision aids. We would give more opportunities by sending people an email before they come for screening that would link them to a website. We’re going to use digital television for people who don’t have the internet. So I think we will give people a lot more information. Of course not everyone welcomes all this knowledge, but I feel we have a duty to provide it.
Alex Barratt: Dr Muir Gray is Program Director of the UK National Screening Committee.
Like Dr Gray, Professor Glasziou at Oxford University feels there is a need to give people better information about screening. He would also like to see more consumer input into the development of screening policy, through a process of community consent. Professor Glasziou.
Paul Glasziou: We take a representative group and get that group to be fully informed about it. Make sure that they understand it and ask them what they think. And they could give us a decision and say yes I think you clearly should do this. But they may also say, no I don’t believe this is an appropriate thing.
In the UK there is a lot of talk about patient choice. This would actually be a real expression of patient choice in the screening programs that I think is absolutely essential.
Alex Barratt: Professor Paul Glasziou from Oxford University.
This is the Health Report on ABC Radio National and I’m Alex Barratt. You’re listening to the third and final part of a series on cancer screening. In a minute we’ll look at what you can do to make a decision that’s right for you. But before that let’s just stay with the societal perspective for a little longer.
Given that screening is expensive and it’s a close call, is there a case for reducing funding for it? I asked Dr Welch if he thought it might be better to direct funding away from cancer screening and towards cancer treatment services?
Gilbert Welch: I think that’s a very reasonable question. I think we probably overstated the value of screening and probably undervalued the importance of treating people with established disease. When you have a new breast lump, go see your doctor. That’s not screening, that’s people who have early symptoms coming in and seeking treatment. All doctors think that’s important.
So in general I think our money is best spent when it comes to cancer to dealing with people with established disease, or removing the risk factors that put people at risk for cancer, particularly smoking.
Alex Barratt: Dr Gil Welch, US Department of Veterans Affairs. So maybe there are better ways to spend our health care dollars. I put that to Professor Glasziou.
Paul Glasziou: That’s a very good question and a very difficult debate. This is what the health economists call cost effectiveness analysis. And what they have suggested we should do is say what all the things we could do for the community are – in terms of health benefits. And say, which ones would be most value to the community, given that we’ve got a limited budget to spend on health? For example the single largest factor in the community causing unnecessary morbidity and mortality is smoking. So if you can get people to give up or if we can stop teenagers taking it up that would be the single most effective thing we could do, and is extremely good value for money. We could increase the range of chemotherapeutic agents. But some of those aren’t particularly cost effective. Providing broader access to standard treatments and making sure that they occur in a timely fashion would certainly be a good thing to do.
Alex Barratt: Professor Paul Glasziou, University of Oxford.
That’s the end of this segment of the program in which we have been looking at the forces that drive cancer screening, and how they might change in the future. Now it’s time to apply all this to real life. How can you use this information to make decisions about being screened, whether you’re a man considering prostate or bowel cancer screening, or a woman considering breast, bowel or cervical cancer screening? Well the first thing to realise is there’s no single right answer. People can, and do come to valid and rational but different decisions.
Dorothy: I’m 64 years old. I think having had breast cancer that you still always live with that fear that it’s going to return. I still have my regular mammogram done every 12 months and an ultrasound done. I think every woman should have a mammogram done. Either every two years or if there is a sign of breast cancer in the family, it should be done every 12 months. I’m very much in favour of the mammograms being done.
Woman: I’m 72. I’ve had mammography and I’ve had pap smears. Now I don’t see any point in doing those tests after you are 70. Either they won’t detect anything in which it’s a waste of time. Or it will be indefinite and then there will be a whole lot more tests which is more waste of time. Even if they do find something and it’s going to kill me, well something’s going to kill me. I’d just as soon it was cancer than that I went into a home with dementia. I certainly don’t want to go into a home with dementia. So that’s why I don’t do it.
Alex Barratt: So how do you come to your decision? Here’s Dr Welch again with some thoughts on how to assess the various offers of cancer screening that are likely to come your way.
Gilbert Welch: It is a close call and you do have to ask yourself to what extent you want to participate in all these screenings. Because I think they’re only going to continue to explode. And so I encourage people to try and understand the basic principles involved so they can understand some of the trade-offs.
I think the other thing they need to do is when people are being offered a test by their physician or told that they should have a test, they should ask some hard questions. And one very simple question is why are you recommending this test. Is it something that your institution is encouraging you to do? Do you really believe in them? Do you have something to gain from it?
I think the second level question is, are there any true experiments on the value of this test. That is, are there any randomised trials? And if your physician doesn’t know the answer to that you have to be prepared for that, and then you might want to look into it a little bit more yourself. And you should know that most of these tests have not been subjected to randomised trials. And that’s important to know because that means we really don’t know whether they are going to help you or not.
And then the third question I encourage people to ask, just so they get some sense of what’s there in the future, is, if I have a positive test what will we do next? And if the answer to that question is something you don’t want to do and you would never do, then you might as well not get the test. There’s no reason to start getting tests if you’re not going to act on them.
Alex Barratt: You’re not saying people should stop screening. I think what you are advocating is that people should be given more and better balanced information about screening, so that they can make their own decision about whether to attend or not.
Gilbert Welch: Absolutely right. There’s no right answer here. So I think it’s really important that we at least give a balanced message about the upsides and the downsides of cancer screening, and let people choose what they want.
Alex Barratt: To help people with their decisions some groups are developing interactive information tools, or decision aids about screening for people who want to make an informed choice. Professor Annette 0’Connor is a professor in nursing and clinical epidemiology at the University of Ottawa in Canada. She’s led the world in the development of patient decision aids.
Annette O’Connor: Patient decision aids are usually reserved for the tougher types of decisions. When you see your doctor about a baby’s ear infection they might prescribe an antibiotic, or if you have a pain here they might suggest a remedy. And it’s pretty straightforward and nobody needs a decision aid to work through those issues. But there are some issues in health care or some decisions that are a little bit tougher. Where there’s more than one reasonable option and there may be some benefits and harms that people have a different view on.
Some people think the benefits outweigh the harms and other people think the harms outweigh the benefits. Some examples would be birth control. Lots of options. They all have pros and cons and people need to think about it and obviously it is a personal decision.
Another example would be if you have breast cancer. Most women with early breast cancer get offered a lumpectomy with radiation or a mastectomy. The survival rates are the same, so it’s a personal decision on which option you want.
So a decision aid could be a video, could be a paper-based tool, it can be on the internet as a sort of interactive program. So it’s delivered in different ways, depending on what a person needs and access to information. And it defines what the condition is, why are you having to consider this issue and then what are the options and what are the benefits and harms of these options. And how do I go about preparing myself to consider what’s important to me so I can have a discussion with my doctor about the pros and cons of the options.
Alex Barratt: And if I use one what’s it going to do for me?
Annette O’Connor: Well it prepares you to discuss these sort of controversial areas in a more reasoned way with your practitioners. So they have to spend less time giving you the facts and you can spend more time talking to them about what matters most to you. Because what we’ve found in most analysis of doctor interviews is that they spend too much time giving the facts and not enough time listening to what matters most to the patient.
Alex Barratt: Do we know if it leads to better decisions?
Annette O’Connor: It does because for these decisions there’s no right or wrong answer. So what we’ve come up with is an international standard defining a good decision. And what we consider a good decision for these tough decisions is that it is an informed decision based on your understanding of the facts and also the chances of benefits and harms. And it’s also a decision that is consistent with what matters most to you.
Alex Barratt: Professor Annette 0’Connor from the University of Ottawa and the Ottawa Health Research Institute.
STEP, the Screening and Test Evaluation Program at the University of Sydney where I work is looking at the use of decision aids for screening. At present we’re testing a decision aid for women aged around 40 years who are considering whether to start screening mammography. As we’ve heard screening mammography probably reduces the risk of dying from breast cancer among women aged 50 to 69 years. Among younger women the benefits are less, and there are the downsides to consider too.
All up it’s a close call. So many health authorities recommend women in this age group be given the relevant information and supported to make their own decision. This is why we’ve made the decision aid. And now we’re running an online study to see what women think of it.
We’ve tried to make the decision aid as balanced as possible. So it doesn’t encourage you either towards or away from screening. Here are some short extracts from the decision aid.
Woman: This website helps you think about whether you want to start having mammograms to screen for breast cancer, if you are younger than 50. It has information about the issues you may want to consider in making your decision. The website also contains a worksheet to help you make your decision and examples of how other people might make the decision.
1. What happens to women aged 40 who screen or don’t screen?
Out of 1000 women aged 40 who start having screening mammograms, two women will die from breast cancer over the next ten years.
Out of 1000 women aged 40 who do not have screening mammograms, 2.5 women will die from breast cancer over the next ten years.
2. What else happens to 1000 women aged 40 who have screening mammograms over the next ten years?
21 women are diagnosed with breast cancer.
239 women will have extra tests after an abnormal mammogram. The extra tests will show these women don’t have breast cancer. These are false alarms.
740 women will be correctly reassured they do not have breast cancer.
Among 1000 women who do not have screening mammograms, 14 will develop symptoms and be diagnosed with breast cancer.
What to do next?
EXAMPLE ONE
Ms K is 39 years old. Her older sister and mother have had breast cancer. Ms K feels that her family history and the large number of women who will be reassured by screening that they don’t have breast cancer both make her want to start screening. But she feels that the women who have had false alarms make her not want to start.
Ms K weighs up these points. Although she has strong feelings about the women who have false alarms, she feels that her reasons to start screening, especially her increased breast cancer risk outweigh this. She decides to have a mammogram when she turns 40.
EXAMPLE TWO
Mrs P is 42 years old. She has no breast cancer risk factors, but a close friend has just been diagnosed with breast cancer at age 46. Mrs P feels that her friend’s diagnosis and the women reassured that they don’t have breast cancer make her want to start screening. She feels that the extra women diagnosed with cancer, the women who have false alarms and that she has no risk factors are all reasons for her not to start screening.
She weighs up these points. Although she has very strong feelings about her friend’s breast cancer diagnosis and would like to be re-assured that she does not have breast cancer she feels the points against screening outweigh the reasons to start. She’s thinking she will wait until she is 50 to start screening.
Alex Barratt: If you would like to participate in the online study of this decision aid go to abc.net.au/rn. Follow the links to the Health Report and from there to the STEP website and the 40 year olds screening mammography decision aid. We’d love to know what you think of it.
You need to be a woman around 40 years of age to be eligible to participate. There’s no need to provide any identifying information. You can also read about cancer screening in detail in a book written by Dr Gil Welch, called ‘Should I be tested for cancer – Maybe not and here’s why’, published by the University of California Press.
I would especially like to thank all the people who shared their stories about cancer screening, and also my thanks to the experts who contributed their time and expertise.
These programs were produced by Brigitte Seega, with technical production by Janita Palmer.
Norman Swan: That series was made by Associate Professor Alex Barratt who’s in the School of Public Health at the University of Sydney.
Guests
Dr Gilbert Welch
Professor of Medicine Dartmouth Medical School New Hampshire USA
Professor Paul Glasziou
Centre for Evidence-based Medicine Oxford University UK
Dr Angela Raffle
NHS Breast and Cervical Cancer Screening Programs Bristol, UK
Dr Glenn Salkeld
Associate Professor of Health Economics University of Sydney Sydney, New South Wales
Dr Muir Gray
Program Director UK National Screening Committee
Dr Annette O’Connor
Professor of Nursing and Clinical Epidemiology University of Ottawa Ottawa Health Research Institute Canada
Further Information
Australian Screening Mammography Decision Trial
School of Public Health Sydney University
http://www.mammogram.med.usyd.edu.au/
Cancer screening: is it worth it?
http://www.abc.net.au/health/thepulse/s1438910.htm
