Prostate cancer conundrum

MORE MEN die from prostate cancer than from any other form of the disease besides lung cancer. The development of a PSA blood test, followed by biopsies for worrisome results from the test, was supposed to bring down this death rate. But two recent large studies, one in the United States and one in Europe, indicate that the screening is causing overdiagnosis and overtreatment - with little if any gain in lives saved. The National Institutes of Health and other funders of research should put a premium on supporting scientists looking for a marker that distinguishes between aggressive prostate cancers and what scientists call "indolent" cancers.
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The human cost to overdiagnosis begins with anxiety and ends, in many cases, with surgery or treatment with radiation. Incontinence and impotence are common side effects. The cost to society is hundreds of millions of dollars spent on biopsies, treatments, and lost work time for handling cancers that in most cases would not become life-threatening. The researchers in the European study calculated that they would have to screen 1,410 men and treat 48 men for every one whose life was saved.

Granted, mortality rates for prostate cancer have fallen slightly in the decades since the PSA (prostate-specific antigen) screening became common. But researchers believe this might reflect not so much screening as improved treatment, including the use of hormones to keep the cancer at bay in older patients.

Despite the studies' finding of limited gains in lives saved by screening, many men will continue to ask for the test and put up with biopsies and treatment for the assurance of protecting themselves from a cancer that kills more than 28,000 Americans each year. "Some well-informed clinicians and patients will still see these trade-offs as favorable," wrote Harvard Medical School's Dr. Michael Barry in an editorial accompanying the studies in the New England Journal of Medicine. "Others will see them as unfavorable." He said the studies buttress the case for shared decision-making about the PSA test by men and their doctors.

But the studies also demonstrate the need for better tools to weigh the actual danger presented by the cancerous cells in a patient's prostate. An official at the National Cancer Institute in Bethesda, Md., says at least four new prostate tests are being studied in people, including a urine test that looks for an amino acid called sarcosine that rises when the prostate cancer is active. But it could be a decade before a better test than the PSA is in widespread use. Shortening that timetable would benefit not just men stricken with the disease, but also society as a whole as it tries to bring health costs under control.