Prostate-cancer screening: New research, but still no easy answers[SIZE=-1]
The problem: It turns out that many prostate cancers are unaggressive and may not require any immediate treatment. Yet even those cancers are often detected by the PSA test. And, once found, many people do get treated since it?s hard to identify just the aggressive tumors. Moreover, treatment often leaves men incontinent, impotent, or both. Perhaps most worrisome, researchers had no hard evidence from randomized clinical trials?the gold standard when it comes to medical research?that routine testing for prostate cancer actually saved lives.
As a result, the United States Preventive Services Task Force has said that it doesn't have enough evidence to recommend the test, while the American Cancer Society, which generally endorses cancer screening, simply told men to talk with their doctor about the test?s risks and benefits. And many organizations said they couldn?t give firmer advice until the results of reliable trials came in.
Well, two such studies published early results today in The New England Journal of Medicine, and guess what: The controversy continues. One of the studies, of 182,000 European men ages 50 through 74 who were followed for an average of nine years, found that for men between 55 and 69 PSA screening cuts prostate cancer deaths by 20 percent. But the other, a U.S. study of 76,693 men ages 55-74 years followed for ten years, found no mortality benefit.
Why the difference? Maybe it?s because the European study included a lower PSA cut off; doctors generally biopsied men whose PSA level was over 3 nanograms per milliliter, instead of 4 ng/ml as in the American study. But adopting that lower threshold isn?t necessarily a simple solution. That?s because the lower cut-off point may have led to a high rate of overdiagnosis and overtreatment. The European researchers themselves note that to prevent one prostate cancer death, 1,068 men would have to be screened, and, of those, 48 men would have to undergo cancer treatments, with all the attendant costs and risks.
Is that a risk-benefit ratio you?re willing to accept? For some, maybe it is. For others, maybe not. , ?The implications of the trade-offs reflected in the data, like beauty, will be in the eye of the beholder,? wrote Michael J. Barry, M.D., a Harvard Medical School professor, in an accompanying editorial. ?As a result, a shared decision-making approach to PSA screening, as recommended by most guidelines, seems more appropriate than ever,? he says.
CR?s take: There is little reason for men over age 75 to get their PSA tested, since the cancer typically progresses so slowly that even if prostate cancer is detected they are more likely to die with the disease than of it. And black men under age 45 and other men under age 50 usually don't need the test either, since the disease doesn?t become common until after those ages. For other men, we agree with Dr. Barry: shared-decision making is essential. And that doesn't mean just accepting your doctor?s advice to avoid or, more likely, have the test. It means learning as much about it as you can, including the variations that some doctors now use as well as the possible treatments, should you find that you do have cancer. (For details, see our prostate cancer Treatment Ratings*- for subscribers only.) And have an honest discussion with your doctor that includes a careful assessment not just of your medical and family history but also your feelings about cancer and the potential side effects of treatment.
--Kevin McCarthy, associate editor and Joel Keehn, senior editor
Read more on the risk factors for prostate cancer*and the latest research on finasteride. And if you've been diagnosed with prostate cancer, take a look at our list of questions to ask your doctor.
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