PSA: To test or not to test, from Harvard Men’s Health Watch

One of the most controversial issues in men’s health is whether men should routinely have a blood test for prostate-specific antigen (PSA) to screen for prostate cancer. Some experts argue that PSA testing saves lives by helping detect this common form of cancer early. Others say it triggers unnecessary treatment that disrupts many more lives than it saves. The results of two studies released this spring focused the debate, but scientists are still a long way from concluding the discussion, reports the July 2009 issue of Harvard Men’s Health Watch.

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.

Read the full-length article: "PSA: Prostate-Specific Antigen, Persisting Scientific Ambiguities"