Opinion

A Tyee Series

Screening for Prostate Cancer: 'Poster Child' for Overdiagnosis

Before you get that test, know the potential problems as well as payoffs. Fifth in a series on medical screening.

By Alan Cassels, 10 Aug 2011, TheTyee.ca

A doctor and patient

Screening men over 55 didn't save lives: US study.

"Traditionally, doctors have focused on the one out of 1,000 we might help by looking for early forms of disease. But we haven't really asked the question, what happens to the other 999? And this problem was really demonstrated to us in prostate cancer screening, which is really a poster child for the problem of overdiagnosis." -- Dr. Gilbert Welch, author of Overdiagnosed: Making People Sick in the Pursuit of Health

In a very frank statement to the New York Times in Oct. 2009, Dr. Otis Brawley, the chief medical officer of the American Cancer Society, said "we don't want people to panic but I'm admitting that American medicine has overpromised when it comes to screening."

This is a remarkable statement coming from an organization that is among the world's biggest promoters of medical screening. Their pleas for everyone to become active participants in cancer prevention -- telling us to get screened early and often -- have been drilled into us for decades. In fact the "Test Early Test Often" is axiomatic in the cancer world, where we are repeatedly told that early detection is the key to survival. Our doctors largely follow that mantra, ordering annual tests of our prostates, our breasts, our colons and our cervixes according to screening guidelines. The logic of cancer screening is reinforced through a very simple message: find disease early before it gets you.

One of the problems about the overpromises of cancer screening referred to by Dr. Brawley is that while we are getting very good -- some might say too good -- at finding hidden cancers using modern technology, we're not always so good about doing the right thing when we find it. In fact, cancer screening, once accepted as a given, almost a motherhood issue, is starting to be more and more questioned. Experts are not the only ones becoming more and more vocal in asking hard questions around screening, and prospective patients too are weighing in with such questions as: Are the tests specific enough in finding only those cancers that will go on to hurt us? Is it possible that cancer screening can adversely affect the quality and length of my life? If I go to the trouble to be screened will this ultimately lead to my life being saved?

The last two years have seen a spike in interest in these kinds of questions, because as more research comes in it is increasingly clear that the evidence isn't keeping up with the hype. If cancer screening was living up to its billing we would be finding earlier cancers -- the ones that in the past were usually found too late -- and saving lives that would otherwise be lost. This might be the case with colon and cervical cancer screening, but it isn't with probably the two most controversial cancer screening programs around, those for prostate cancer or breast cancer (topic of the next story in this series).

While screening for these two types of cancer may find deadly tumours, what seems to be downplayed in much of the literature is the fact that screening can cause considerable collateral damage, including invasive biopsies, surgery, hospitalizations, infections and even deaths. Again, we're not talking about sick people here; we're talking about people who are well, have no symptoms, who are screened and told they have tumours within their organs. And in many cases, those tumours may never have been a problem. A study published a few years ago in the Journal of the American Medical Association found that society's aggressive promotion of prostate cancer and breast cancer screening was resulting in a massive increase in the numbers of low-risk cancers found but not reducing the number of aggressively growing cancers found.

The results: lots more cancer diagnoses, but no additional lives being saved.

Sold as a life saver

Prostate screening typically involves both a digital rectal exam and a PSA test, a blood test that measures a protein produced by the prostate, a walnut-sized gland which surrounds the uretha. If you have a "high" PSA reading it could mean a lot of things, such as inflammation or infection of the prostate. Or it could mean cancer.

The first thing a man might be told regarding PSA testing is that it will save his life, thus creating a pretty strong motivation to submit to a test. The evidence behind PSA testing, however, shows it to be much less than a slam dunk. Two recently published studies, one in the U.S. and one in Europe added even more uncertainty to the equation by producing contradictory results.

The U.S. study showed that there were no additional lives saved by carrying out PSA screening following men 55 and over after seven to 10 years of follow up. PSA screening essentially did not change the death rate.

The study from Europe showed some decline in death rates in men who were screened but the results are somewhat unimpressive. It found that to save one life, 1,410 men would need to be screened and 48 men would need to be treated. What happens to the other 1,409 men screened and the 47 who undergo treatment but would otherwise not have been killed by the cancer? Screening itself can cause anxiety, and begin a cascade of further interventions, like biopsies of the prostate and infections, some of which can be deadly. Many of those men who get treated with chemotherapy, surgery or both end up impotent or incontinent.

Let's be clear: PSA testing can detect prostate cancer early. Treatment for prostate cancer may be more effective when it's found early. However, prostate cancer screening can result in false positive results (the PSA test could show you have prostate cancer when in fact you do not) leading to further tests and more anxiety. Referring to the grim realilty of the unpleasant side effects of treatment, such as sexual dysfunction (impotence) or incontinence (inability to control the flow of urine) one doctor once told me: "Prostate treatment may not help you live longer, but it will make your life feel longer."

HELP IN DECIDING

Luckily, there are some good sources of literature on prostate screening. The Center for Disease Control in the U.S. has produced a noteworthy decision guide to prostate screening. To find it, click here.

Most men over 60 have prostate cancer

What is very hard for most of us to understand is that many cancers can be so slow growing they would never spread and kill. The simple fact is that 60 per cent of men in their 60s have some form of prostate cancer; overall, we men have about a three per cent lifetime risk of dying from it. Most men, who live long enough, die with prostate cancer, but not because of it. Having said that, if you have any symptoms whatsoever, such as difficulty peeing, you should get things checked out. The hard part for most men who have been told they have prostate cancer is being offered no treatment whatsoever, a phenomenon called "watchful waiting." Just waiting and seeing what happens is a viable course of action, because most of the time nothing bad will happen. But this goes against the best instincts of many of us who would say, "I've got cancer? Okay, doc, go ahead, do whatever cutting and chemo you need to do to get rid of it."

The evidence around PSA testing has become an incredibly fast moving target and while things are confusing for men, it is doubly confusing for physicians who counsel men on it. Perhaps the current state of PSA screening is best summed up by Dr. Jeff Susman who wrote, in a recent editorial in the Journal of Family Practice, "Keeping up with this area of practice is beginning to feel like a full-time job."

Besides the potential for false positives, perhaps the most worrisome thing about PSA testing is that it creates a huge demand for biopsy tests, which use needles to pierce the prostate and are themselves capable of making perfectly healthy men sick. The biopsy carries an infection risk, because the needles used in the biopsy can sometimes take bacteria from the bowel into the prostate, bladder and bloodstream. A recent story in Bloomberg News reported that as many as five per cent of men undergoing a prostate biopsy may experience serious, life-threatening infections.

Dr. Jeff Susman, who hopes better screening techniques are coming down the road, writes, point blank, that "it is time to stop this screening nonsense." For him, the promotion of PSA screening needs to end: "it is time for urologists and primary care physicians to tell patients that PSA screening is unlikely to benefit them."

Despite all the controversies around PSA testing, between those promoting it and those trying to rein things in, there is one solid and indisputable common ground: men need to go into prostate screening with their eyes wide open -- and they need to agree to it only after a full assessment of the possible good, the bad and the ugly of PSA testing. Perhaps the best place to start is reading a reasonably good and informative factsheet, and preparing yourself for the inevitable discussion with your doctors.

Has modern medicine overpromised when it comes to saving men from prostate cancer deaths? Undoubtedly, it has. Perhaps now is the time to balance out those promises with another promise: let no man submit to a PSA test looking for prostate cancer until he is clear on what could happen as they look for it, and what could happen if they find it.  [Tyee]

7  Comments:

Login or register to post comments

  • snert

    41 weeks ago

    Nothing wrong with PSA tests.

    It's the resulting actions that create the issues. These are the areas that need a huge amount of work.

    The PSA test should be viewed as just one of the tests along the route to a diagnosis of cancer. Maybe a biopsy should not be an automatic response. Maybe the medical profession should come up with a kinder, gentler form of biopsy.

    I'm sorry but "Most men over 60 have prostate cancer" just doesn't cut it. So what, that means you stop trying to hunt down the ones with the most virulent kind?

    This is not a case of overdiagnosis. It's a case not being able to develop proper screening procedures.

  • wanderingraven

    41 weeks ago

    Great article

    The trouble with the screening is that it creates the pressure to 'do something' even though doing nothing may be the better option.

    It's certainly a worthwhile endeavour to measure the quality of life-years saved against the quality of life-years destroyed when analysing this issue.

  • snert

    41 weeks ago

    wanderingraven

    We're not just talking screening here but woefully inadequate screening. That's where this article falls flat on it's face.

  • zalm

    41 weeks ago

    Well said

    The relationship betweent he patient and the primary care physician does the most to forward or retard the investigations at the most appropriate level.

    In Canada, most specialists on this coast tend to be pretty busy, and if you decide you're not going to do something, , well, move along, the guy right behind you is waiting to come in and have a talk with me. See you again sometime...

    I'm with snert - the screen is not the issue. what would be valuable is to examine the whole-life cost cycle of early intervention versus unnecessary intervention. I remember seeing results of a study that attempted to quantify the comparisons between financial, health and quality of life costs on a different abdominal procedure in an article in CMAJ, but I have no way of searching it out as I've no subscription.

    Perhaps someone will do something like this for prostate screening, if it hasn't already been done.

  • Jeroen

    41 weeks ago

    Family History

    The article fails to distinguish between universal screening for prostate cancer in men over a certain age and targeted screening. While there may be a strong case against universal screening, there is a much weaker case against targeted screening, which takes into account family history. Men whose fathers or brothers have had prostate cancer are at much higher risk themselves and arguably should have the PSA test every year or two. In fact, BC Medical recognizes the difference between the two groups (low risk versus high risk) and will pay for a PSA test for a high risk male but not for a low risk individual.

  • jake the snake

    40 weeks ago

    Urine Test may Predict Prostate Cancer Risk

    Urine Test may Predict Prostate Cancer Risk by Sheela Philomena http://tinyurl.com/4xnev8t

    I'm always amazed that there is no mention of the urine test to screen for prostate cancer. It's been around for a while, I had one June 2010 at the cost of $300. I took a urine sample in a container the Canadian company supplied to my GP, couriered it to a company in Montreal, I think, and got the results which were reassuring. My beef is that such a effective test should cost anything.

  • jake the snake

    40 weeks ago

    Another reference

    U.K. Scientists Unveil 'Superior' Urine Test for Prostate Cancer

    Scientists in the U.K. say they have developed the first reliable test for diagnosing early prostate cancer.

    The urine test is so accurate that it could be used to screen all older men for the disease.

    Read more: http://tinyurl.com/3rstg42

    • The discussion for this story is closed. No more comments can be added.