The US Preventive Services Task Force issued a PSA for men yesterday: stop screening for PSA because it causes more harm than good.
PSAs, short for prostate-specific antigens, are released from damaged prostate tissue. The original screen for the proteins was only intended for diagnosing recurrence of the cancer, but after doctors began using it to detect early prostate cancers, the US Food and Drug Administration approved the test for this indication in 1994. Although the PSA test can help diagnose prostate cancer, it also has high false positive rates because the prostate releases the biomarker during many kinds of damage beside cancer, leading many men to undergo biopsies for non-existent tumors and enduring the associated complications, including fever, pain and bleeding. Additionally, prostate cancer is slow-growing, with many men never showing symptoms. Thus, PSA screening picks up these mostly benign tumors, prompting surgery and radiation therapy, which some argue are unnecessary. (See our December 2009 feature ‘Markers of dispute’ for more on the controvery.)
Now, in draft recommendations published today in the Cancer Letter, the US Preventive Services Task Force is recommending that the PSA test be downgraded from ‘inconclusive’ to ‘no benefit’ for men of any age. “Most trials found no statistically significant effect on prostate cancer-specific mortality,” the task force members wrote in the journal. The test had already been classified as such for men over age 75.
To replace PSA screening, many researchers are hoping to develop a better test. In August, for example, Arul Chinnaiyan and his colleagues at the Michigan Center for Translational Pathology in Ann Arbor published results from a urine test that screens for prostate cancer-specific biomarkers.
“We have put a huge amount of time, effort and energy into PSA screening and that time, effort and energy, that passion, should be going into finding a better test instead of using a test that doesn’t work,” Virginia Moyer of the Baylor College of Medicine in Houston, who headed the task force, told the AP.