(Bloomberg News) PSA screening for prostate cancer used by half of men older than 40 isn't worth the risk of side effects from unnecessary treatment and shouldn't be used to diagnose the disease, a U.S. panel said, affirming its earlier advice.

Scientific studies suggest the number of deaths avoided by screening are "very small" compared with risks from treatment that can include infections, incontinence, erectile dysfunction and death, the U.S. Preventive Services Task Force said. The panel kept its recommendation from October after some doctors and patient groups said discouraging the tests would cost lives.

Prostate cancer was diagnosed in about 250,000 patients last year and caused 33,700 deaths, the task force said. It is the second-most common malignancy among American men. The guidelines may affect whether insurers pay for blood tests measuring PSA, a protein associated at high levels with the disease.

"Many men are being subjected to the harms of treatment of prostate cancer that will never become symptomatic," the panel wrote in a report released yesterday by the Annals of Internal Medicine. "There is convincing evidence that PSA-based screening for prostate cancer results in considerable overtreatment."

The government-sponsored task force is an independent medical advisory group that drew criticism in 2009 for questioning the value of breast-cancer screening in women younger than 50.

In its recommendation, the 16-doctor panel urged against screening for men of all ages, updating a 2008 report that found insufficient evidence to use it in those older than 75. The report cited the slow growth of most prostate tumors as well as false positive rates that may be as high as 80 percent.

Caution For Doctors

While doctors are still free to suggest PSA tests, they should be prepared to discuss the potential downsides, the report said. Community- or employer-offered mass screenings should be discontinued, the group said. The guidelines don't apply to men already diagnosed with the disease.

The findings won the endorsement of the American Cancer Society in an accompanying editorial.

"Americans have been taught for decades to fear all cancer and that the best way to deal with cancer is to find it early and treat it aggressively," said Otis Brawley, the Atlanta-based society's chief medical officer. "As a result, many have blind faith in early detection" with "little appreciation of the harms that screening and medical interventions can cause."

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