Our society has been encouraged to value early cancer diagnosis. But not all cancers are alike. Detecting prostate cancer early is not nearly as important as detecting lung cancer or colon cancer early, because many prostate cancers grow very slowly and don't threaten health. Spotting prostate cancer early usually leads to treatment, but current treatments can cause life-changing side effects such as incontinence and erectile dysfunction. The crux of the controversy is whether screening for prostate cancer using the PSA test does more harm than good. That's the question the new studies—one done in the United States, the other in Europe—were designed to answer.
Half of the volunteers in both studies were randomly assigned to have PSA tests, while the other half simply received their usual medical care. In the studies, men with high PSA levels (above 4.0 ng/mL in the American study and 3.0 ng/mL in the European one) underwent prostate biopsies to look for cancer. The American study found that after seven and 10 years, PSA screening increased the diagnosis of prostate cancer, but did not improve survival. After nine years, the European study found that men who had been screened were less likely to have died of prostate cancer, but at a substantial cost of overdiagnosis and overtreatment.
PSA testing remains a personal decision. But the Harvard Men's Health Watch notes that with the latest results, things have changed. Before these studies, skeptics said there was no evidence that PSA screening saves lives. These studies now support that view. Until now, if a man could not decide whether he should have his PSA checked, the default recommendation was in favor of testing. These studies suggest the opposite strategy might be better—that unless a man has a particular reason to request a test, the default should be to skip it.
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