But men with a poorer outlook should generally avoid screening with the blood test for prostate-specific antigen, or PSA, according to the American Society of Clinical Oncology (ASCO).

"Screening should be discussed with men who have a longer life expectancy, so that men can make an informed decision," said Dr. Ethan Basch, a prostate cancer specialist and co-chair of the ASCO panel.

The new advice, published in the Journal of Clinical Oncology, comes on the heels of a blanket recommendation against prostate cancer screening from the government-backed U.S. Preventive Services Task Force.

When the USPSTF's guidelines were released last May, they triggered an outcry from many cancer specialists and urologists who felt the move could be a death sentence for scores of men across the country.

Dr. Michael LeFevre of the USPSTF stressed the similarities between the two sets of recommendations, but said his organization took a slightly stronger stance against the test.

"We are actually not suggesting that physicians bring up screening with men," he told Reuters Health. If a patient wants the test after getting adequate information about the pros and cons, however, LeFevre said he has no qualms with it.

Prostate cancer is the second-leading killer in men, with more than 240,000 new diagnoses and 28,000 deaths every year. As the PSA test was rolled out over the past two decades, the hope was that it would save lives through early detection and treatment.

But critics fear the test, which is given to millions of Americans every year, has ended up causing more harm than good. In a New York Times op-ed from 2010, for example, Richard Ablin, one of the discoverers of PSA, said it had led to "a hugely expensive public health disaster."

A PSA test costs between $60 and $80. And if blood levels of the antigen are high, men often get follow-up tests or a biopsy to check for signs of cancer in the prostate - a procedure that comes with a much higher price tag.

INCONSISTENT EVIDENCE

Like all other screening tests, checking healthy people for prostate cancer also carries health risks. To gauge how they compare with the potential benefits, ASCO used the same data review that the USPSTF looked at. The two main studies in that review - one European and the other American - yielded mixed conclusions.

The American trial included more than 76,000 men, half of whom were screened systematically while the others got standard care - in some cases involving PSA tests.

The study found screening had no effect on prostate cancer deaths, but drew criticism from some scientists who said potential benefits may have been obscured because some men in the standard care group also got screened.

The European trial was not plagued by that problem. It included some 162,000 men aged 55 to 69 and showed screening actually did cut the number of deaths from prostate cancer. But the effect was small. After 11 years of follow-up, researchers found more than 1,000 men would need to be offered prostate cancer screening for just one to avoid dying from the disease. By the same token, 37 would be diagnosed with cancer and forced to make tough decisions about whether or not to undergo treatment.

What's more, there was no proof that the test saved lives overall. And while the European study was done in eight countries, only Sweden and The Netherlands saw a protective effect of screening.

BALANCING RISKS AND BENEFITS

ASCO concludes that for men who have at least 10 years left, "PSA testing may save lives but is associated with harms, including complications, from unnecessary biopsy, surgery, or radiation treatment."

While life expectancy depends on general health and lifestyle, Basch said a 75-year-old man in the U.S. would live another 10 or 11 years on average.

His group released a decision aid along with its recommendations to help men balance the pros and cons of getting a PSA test (available at www.asco.org/pco/psa).

The document, which is based on the European screening study, explains that out of 1,000 screened men, four will die of prostate cancer, compared to five out of 1,000 men who don't get the PSA test.

On the flip side, three-quarters of all the positive tests will turn out to be false alarms. And nine out of 1,000 men who get a biopsy after a positive PSA test will be hospitalized due to fever or infections of the prostate - a number that is on the rise, according to some studies.

Finally, some prostate cancers are slow-growing or don't grow at all, so they would never have been life-threatening. Yet many men choose to get aggressive treatment - surgery, radiation or hormone treatment - which causes incontinence, impotence or both in 20 percent to 40 percent of patients.

Basch said he used to be biased against the PSA test due to those risks, but had been persuaded that some men might still see a benefit.

"Upon review of the evidence my own views changed," he said.

Still, he warned that many tests are made available to U.S. consumers before they have been carefully vetted, including PSA-based screening.

"The test was not adequately evaluated before it came onto the market," Basch told Reuters Health. "Overtreatment is a real problem. In the United States we treat far too many low-grade cancers."

Dr. Otis Brawley, chief medical officer of the American Cancer Society, said ASCO is just one of a number of groups calling for informed decision-making.

"All of those organizations are now saying that men should be informed about what is known and not known about this test and be allowed to make a choice," Brawley told Reuters Health. "Hospitals and organizations doing mass screenings, they all need to realize they need to stop that."

SOURCE: bit.ly/aaGhWR Journal of Clinical Oncology, July 16, 2012.

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