A common prostate-cancer screening test may be largely ineffective, according to two new studies. Scientists in the U.S. and Europe found that the PSA blood test saves few lives and leads to unnecessary treatments for large numbers of men. The test, which measures a protein released by prostate cells, is used to determine whether a cancer might be present. But scientists have long been uncertain whether early detection of prostate cancer actually saves lives. With the faster-growing cancers, an early diagnosis might still be too late.
Most of the men in the American study were followed over 10 years. Researchers found no reduction in prostate cancer rates among them. After seven years, the death rate was 13 percent lower for men who had not been screened for prostate cancer. The European study found that that the screening only saved seven out of 10,000 men screened and followed over nine years. The study also found no benefit within the first seven years after the screening. Both studies will continue following the men to determine whether there are any longer-term benefits to screening.
Scientists in both studies are concerned that the PSA test leads to unnecessary cancer treatments. Surgical prostate removal can lead to impotence and incontinence, and radiation therapy can sometimes cause painful defecation or chronic diarrhea. Most men over 50 in the United States have been screened for prostate cancer, and over 180,000 men are diagnosed annually.
Companies developing alternative methods of prostate screening include: