updated 9:35 a.m. ET Aug. 6, 2008

NEW YORK - New advice that men over 75 should not be screened for prostate cancer won’t quell the long-standing controversy over the usefulness of the blood test for the disease, cancer experts said Tuesday.

“It stokes the debate, I think,” said Dr. Charles Ryan, a prostate cancer specialist at the University of California, San Francisco.

And several experts are looking ahead to new research that may provide more specific guidance for all age groups.

The U.S. Preventive Services Task Force, a panel of experts who guide national health care, issued its report Monday based on a review of past research. The task force found that screening can detect some cases of prostate cancer, but the benefits of treatment in men over 75 “are small to none.”

The new guidance is the first update by the task force on prostate cancer screening since 2002. Its last report concluded there was insufficient evidence to recommend prostate screening for men of all ages.

Treatment often causes “moderate-to-substantial harms,” including impotence and bladder control and bowel problems, the task force said, without evidence it saves the lives of these elderly men.

The panel did not recommend for or against prostate screening of men under 75 but suggested that doctors discuss the potential benefits and harms of the test with their patients.

“I think it’s a very well done and justifiable recommendation,” said Dr. Barnett Kramer, associate director of disease prevention at the National Institutes of Health. “They continue to say the jury is still out for men under 75.”

INTERACTIVE Prostate cancer: What you need to know

In recent years, there has been a growing debate about the value of the somewhat imprecise PSA blood test to detect cancer, as well as the value of treating most prostate cancers. A positive result from the test must be confirmed by a biopsy. And even then, there is no foolproof method of identifying aggressive tumors from slow-growing ones. A number of experts contend patients are being overtreated.

Prostate cancer is the most common cancer in American men — about 186,000 cases will be diagnosed this year, according to the American Cancer Society. It is the second leading cause of cancer deaths in men. But most tumors grow so slowly they never threaten lives.

Prostate cancer screening is done with two tests: a blood test that measures prostate specific antigen, or PSA, and a digital rectal exam. The blood test is controversial because the PSA level can be high for many reasons. A positive result from the test must be confirmed by a biopsy. And there’s no agreement on the best way to treat it: “watchful waiting,” surgery, hormone therapy, radiation or some combination of those.

Screening is “an area of very intense controversy,” said Dr. Durado Brooks, a prostate cancer specialist for the American Cancer Society. “There are many doctors who believe staunchly that PSA testing should be done in all men and there are probably an equal number of doctors who believe very much that testing is of limited value.”

Most major U.S. medical groups recommend doctors discuss the potential benefits and known harms of prostate screening with their patients and make individual decisions. And most agree routine testing shouldn’t occur before age 50.

The cancer society’s advice for screening doesn’t set an age to stop screening but suggests that men shouldn’t be offered screening if they aren’t expected to live another 10 years, Brooks said

“That’s because every 75-year-old is not created equal,” he said.

While some have health problems and aren’t likely to live long, others are “very active, very vigorous and have minimal health issues, and many of those men are going to live into their late 80s or 90s,” Brooks said.

Ryan, in San Francisco, said age shouldn’t be the sole measure.

“It would be a disservice to patients to have their chronological age be the only factor making important health decisions,” he said. “There are some very young 75-year-olds out there.”

But rather than feel slighted by the recommendation, Dr. William Hahn of the Dana-Farber Cancer Institute in Boston said those over 75 should “feel liberated from having to have the test. It’s one less thing for people over 75 to worry about.”

Kramer said the task force made it clear that doctors shouldn’t do routine screening on those under 75 without discussing it first with the patient. The 60-year-old Kramer said he told his doctor he didn’t want the PSA test, but the lab did the it anyway.

The Cancer Society’s Brooks noted that there are four major studies under way on prostate cancer screening and treatment.

“Hopefully, within the next three or four years, we will have some outcomes from those studies and be able to give a little more definitive guidance to men and physicians,” said Brooks.

Retiree Paul Bockenstedt, of Dayton, Ohio, said he doesn’t agree with the task force recommendation and plans to continue to get screened. He’s 84, in good health, and men in his family have lived past 100, he said. If he were diagnosed with prostate cancer, Bockenstedt said he’d consider getting treatment, depending on his health at the time.

“I’d rather know in my case,” he said.

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