Archive for Thursday, March 19, 2009

Studies don’t end screening controversy

March 19, 2009


— Screening for prostate cancer doesn’t necessarily save lives, and any benefits can come at a high price, according to two, big long-awaited studies. The findings are unlikely to end the debate over the usefulness of routine testing.

The two studies — one in Europe and one in the United States — reached different conclusions. In the U.S., where screening is widely used, researchers reported it did not save lives in a study of 76,000 men. In Europe, where the practice isn’t routine, a study of 162,000 found a modest reduction — about 7 fewer deaths per 10,000 men screened. But that screening put more men at risk of getting treatments they didn’t need.

The studies are continuing and may eventually provide definitive answers, researchers said.

In the meantime, experts say men should do what most guidelines advise: Talk to your doctor about the pros and cons of having the tests before deciding whether it is the right choice for you.

The studies were released Wednesday by the New England Journal of Medicine in connection with a conference in Sweden.

“The hope was there that there’d be a clear answer. Either that there was so little or no benefit that it clearly wasn’t worth the risks. Or that the benefit was so large, that it was,” said Dr. Michael Barry of Massachusetts General Hospital, who wrote an accompanying editorial in the journal. “What we’re left with is something in between — that the benefit is fairly small ... and the risks are pretty big.”

Prostate cancer is the most common cancer in men in the U.S. and Europe. More than 186,000 cases will be diagnosed this year in American men and 28,660 will die of the disease.

Screening is done with a blood test that measures prostate specific antigen, or PSA. Levels of PSA can be high for many reasons and a biopsy is needed to confirm a tumor. Many tumors grow so slowly that they won’t be a threat, but there’s no sure way to tell which are the dangerous ones.

And there’s no agreement on the best treatment approach — “watchful waiting,” surgery, hormone therapy or radiation. The treatments can lead to impotence and incontinence.

No major medical group recommends routine screening because there’s no proof that it actually saves lives. That’s the question the teams of researchers took on when the studies began in the 1990s.

Both groups are reporting their results a few years early. In the U.S., a panel monitoring the research decided there was enough evidence so far that screening wasn’t saving lives and may have been leading to unnecessary treatment with serious side effects.

The European researchers noted a high risk of overdiagnosis — the finding and treating of cancers that wouldn’t threaten lives. They said 48 additional men would need to be treated to prevent one death from prostate cancer.

“My interpretation of the two studies together is that PSA screening likely does save some lives but does significant more harm,” said Dr. Otis Brawley, the American Cancer Society’s chief medical officer.


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