NEW YORK — Two big, long-awaited prostate cancer studies published Wednesday found that screening for the disease may save a few lives, but at a high price. The findings are unlikely to end the debate over the usefulness of routine testing for the most common cancer in men.
The two studies — one in Europe and one in the United States — reached different conclusions. In the United States, 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 more 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 United States 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.
Both groups are reporting their results a few years early. In the United States, 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.
That study involved 76,693 men ages 55 to 74 from 10 cities. After seven to 10 years of followup, more cases of prostate cancer were found in the group that got annual screening, but there was no difference between the groups in the number of cancer deaths. The researchers plan to follow all the men for at least 13 years.
What's needed, the researchers said, is a better way to tell which prostate cancers need to be treated.
"When we find prostate cancer, we don't know if it is a killer cancer or what has been termed a toothless lion — the kind of cancer that men will die with, not of," said the U.S. study's leader, Dr. Gerald Andriole of Washington University School of Medicine in St. Louis.