Prostate Cancer Screening Shows No Benefit By TARA PARKER-POPE Updated findings from one of the largest studies of prostate cancer screening show that the commonly used P.S.A. blood test did not save lives, although questions remain about whether younger men or those at very high risk for the disease might benefit. Last fall, the United States Preventive Services Task Force concluded that healthy men should no longer be routinely screened for prostate cancer using the prostate-specific antigen, or P.S.A., blood test. That decision was based on findings from five well-controlled clinical trials, including a major American study called the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial, which studied P.S.A. testing in nearly 77,000 men ages 55 to 74. In 2009, the PLCO trial reported that although annual P.S.A. screening did detect more cancers, it didn’t save more lives when compared with a group of men who were given routine medical care and tested for prostate cancer only when a problem was suspected. But at the time, the investigators had only 7 to 10 years of data. Because prostate cancer can take several years to develop, the investigators continued to collect data after reporting the initial findings. In a new paper published today in The Journal of the National Cancer Institute, the scientists report that the additional follow-up time didn’t change the overall conclusion: that regular P.S.A. testing does not save lives and can lead to aggressive treatments that leave men impotent, incontinent or both. The P.S.A. test, often given to men starting at age 50, detects a protein called prostate-specific antigen and can identify the presence of cancerous cells in the prostate. Although about 12 percent more cancers were found among men in the screening group, the risk of dying of prostate cancer in the study was about the same for each group, whether the cancer was detected through screening or because a man developed symptoms. The findings suggest that the type of cancer typically detected by screening is so slow-growing that it often is unlikely to cause harm before the man dies of another cause. “Despite additional follow-up, there is no demonstrable mortality benefit for the men who had P.S.A. testing compared to the usual care group,’’ said Dr. Gerald L. Andriole, the lead author and chief of urology at Washington University School of Medicine in St. Louis. Even so, the findings are unlikely to resolve the debate around P.S.A. testing. Many doctors argue that the trial was seriously flawed because about half the men in the non-screening group ended up getting one or more P.S.A. tests during the trial period, making it difficult to determine the real effect of screening. After the study was finished, additional analysis also raised questions about whether certain younger, healthy men might benefit from P.S.A. testing. Although only about 300 men out of the 77,000 studied ended up dying of prostate cancer, the test appeared to have saved a few extra lives among younger men who didn’t have other health problems like diabetes or high blood pressure. While that doesn’t change the overall finding that the risks of P.S.A. testing outweigh the benefits, Dr. Andriole said it may prompt additional research into whether younger men should get a baseline P.S.A. test or whether certain groups at higher risk for prostate cancer, like African-Americans or men with a strong family history of the disease, may benefit from routine screening. “I think it supports the recommendation that for the average man in the United States, mass screening is probably not beneficial at all,’’ Dr. Andriole said. “It also will keep the discussion open about whether there are indeed subsets of men who do potentially stand to benefit from P.S.A. screening.”
Posted on: Tue, 11 Jun 2013 03:58:55 +0000
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