PSA screening: What doctors tell their patients
Our editorial board polled 15 Harvard-affiliated physicians — a decidedly unscientific survey — to find out what they tell patients about prostate-specific antigen (PSA) screening. Most of those polled are internists, the medical practitioners most likely to have a discussion with a patient about the risks and potential benefits of PSA screening. Interestingly, the findings from the American Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial and the European Randomized Study of Screening for Prostate Cancer (ERSPC) did nothing to change their recommendations: without exception, what they tell patients now is no different from what they told patients before the studies were published at the end of March. A representative sample of replies follows.
“Since many prostate cancers are slow-growing and never spread, and since treatments for prostate cancer have side effects, to have value a screening test must be shown to reduce a patient’s risk of suffering (both from the disease and from treatment side effects) and risk of death. This has not yet been shown for the PSA test, based on these two long-awaited recent studies. Until and unless it is, I won’t routinely screen the average man (without any risk factors for prostate cancer) with PSA testing. But since I don’t think it’s been conclusively shown that PSA testing does not reduce a patient’s risk of suffering, I will obtain the test if a patient wants it, after hearing my assessment of the evidence.”
— Anthony L. Komaroff, M.D.
“The ERSPC and PLCO trials finally give us some quantitative sense of the trade-offs between the benefits and harms of PSA screening. Men in the United States have about a 3% risk of eventually dying of prostate cancer. At best, if the ERSPC estimate is correct, and not the result of chance or bias, a man who chooses regular screening could lower that risk by about 20%, or to about 2.4%. However, he’d raise his risk of having to eventually face a diagnosis of prostate cancer by 70%, or from about 10% to 17%. More aggressive screening strategies than the ERSPC (annual screening, using lower PSA thresholds to recommend biopsy, using PSA velocity in addition to the PSA level) would drive the risk of eventually facing a diagnosis of prostate cancer even higher, for uncertain benefits.
“I remind men that if they worry too much about their 3% risk of eventually dying of prostate cancer, they may not worry enough about all the other things that collectively have a risk of 97%.”
— Michael J. Barry, M.D.
“If patients ask, as they often do, I explain that PSA testing is like most of the rest of what I do during an annual exam, which is to screen for changes. I explain that an isolated PSA elevation means very little on its own, and that I have many patients with ‘elevated’ PSA levels who are perfectly healthy, with no evidence of prostate cancer. However, I explain that changes in the PSA level over time raise my level of alertness, just like changes in blood pressure, weight, heart sounds, or reflexes do. I also point out that these studies simply make the same point. That is to say, if we just look at PSA levels in isolation, there will not be a good correlation with diagnosing and stopping aggressive cancers. In my entire practice of several thousand male patients, I have only two patients who refuse PSA testing.”
— Martin P. Solomon, M.D.
“By the sixth year of the American study, 52% of men who were randomized to no PSA screening were screened (on their own accord). This is called contamination. The study designers knew it could be a problem, so they powered both the American and European studies to overcome a 20% contamination rate. (In 1998, the PLCO trial increased the number of participants to overcome a 38% contamination rate.) The European study had less of an issue with contamination, mainly because European doctors use the PSA test so infrequently. This explains why we see a 20% reduction in death from prostate cancer in the European study, but not in the American study. Given the contamination issue, we likely will never see a difference in the American study.
“I tell patients PSA screening works and decreases mortality, but they should get it only if they are in reasonable health. You don’t want to die of another cause immediately after you’ve gone through treatment for prostate cancer.”
— Anthony V. D’Amico, M.D., Ph.D.
“The issue of overdiagnosis and the idea of having a cancer but not wanting to know about it is difficult for many men to understand. Because people perceive cancer as ‘bad,’ they want to know if they have it — and get rid of it. I try to help them understand that many prostate cancers don’t need to be treated because they might never cause symptoms. The ERSPC reported that 48 men need to be treated to prevent one death — a useful number to demonstrate the potential harms of screening.
“For men older than 75 or those with other significant conditions that will likely limit their life expectancy, I recommend against routine screening. For other men, I discuss the pros and cons. I’m more likely to recommend screening for men with a family history of prostate cancer and for African American men, because their cancers can be more aggressive, although data to support this are lacking.
“Because both studies are ongoing, it might have been nice if they’d waited to publish until they had more data. But clearly, the studies help us understand that PSA screening is not the magic bullet many folks think it is or should be.”
— Nancy L. Keating, M.D.
“I’ll tell a man at average risk for prostate cancer that the value of PSA testing is a mixed bag — even if he has insurance to pay for the test and any follow-up care. The test may diagnose prostate cancer, but even if he has the disease, his life span is unlikely to be altered if the cancer goes untreated. However, treatment may have a significant adverse impact on his quality of life.
“My approach is a little different for men with a family history of prostate cancer diagnosed at a younger age and for African American men. I tell them the same thing, but I add that there may be some additional survival benefit for them compared to men at average risk.
“Some men’s lives will definitely be saved by prostate cancer screening. If you want to decrease your risk of dying from prostate cancer, no matter what possible side effects may occur from surgery or radiation, then your health belief model would suggest that regular screening is right for you.”
— Howard E. LeWine, M.D.
“For all their differences, the PSA advocates and PSA skeptics have agreed on one point: the only way to resolve the issue is with randomized clinical trials. That’s why the PLCO and ERSPC trials are so important.
“Both are large, high-quality randomized clinical trials, but like all such research studies, they have potential shortcomings, and they are already triggering discussion and debate. Still, they agree that PSA screening produces little or no reduction in prostate cancer mortality. And although the studies have not yet released data on the side effects of treatment, it is likely that since screening does not substantially reduce the risk of death, the side effects of overdiagnosis and overtreatment will mean that screening does more harm than good.
“I have long maintained that while there is no right answer about PSA screening, there are two wrong answers: you must be tested, and you should never be tested. As before, each man should consult with his physician (and often his spouse), then decide for himself. And the decision can change from year to year as new information comes in.”
— Harvey B. Simon, M.D.
“Most men assume it is a good and useful test that is either ‘positive’ or ‘negative.’ I tell them it is a flawed test that might or might not be helpful to their health. If they want to hear more, I explain false positives and false negatives and the whole issue of not knowing in the present what a prostate cancer will do in the future if treated or untreated. Very few men decline testing.
“In the aggregate, the studies do not change my opinion about the flawed nature of this test. It is almost impossible to know who we are helping and who we are hurting with PSA screening.”
— Richard A. Parker, M.D.
Originally published September 2009; last updated on March 16, 2011.
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