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Studies on prostate cancer screening inconclusive
There is now a partial answer to one of the most controversial questions in medicine: whether men should get blood tests that screen for prostate cancer.
Experts say that if men are old or sick and likely to die within 10 years, the answer is no.
But for men in their 50s and 60s who aren't considered at high risk, it's still not clear whether blood tests for prostate-specific antigen (PSA) should be recommended.
Screening tests aren't generally suggested when the potential benefits -- identifying disease early, intervening, saving lives -- are outweighed by the potential risks, physicians explain.
With prostate cancer, most tumors grow extremely slowly and the frequent side effects of treatment -- incontinence and impotence -- are especially disturbing.
The findings come from a new study of nearly 77,000 men sponsored by the National Cancer Institute, the most extensive investigation of its kind in the United States.
Physicians hope the research will offer decisive guidance on prostate cancer screening when it's completed years from now, but decided to release a preliminary subset of results ahead of schedule because of their importance.
The findings were published online Wednesday in the New England Journal of Medicine.
Digital rectal exams also are used to detect prostate cancer, but the exams detect cancers an average of 10 years later than PSA testing. In the United States, digital exams are recommended for low-risk men starting at age 50.
The research was designed to address concerns over the large numbers of men who are getting PSA tests, then being diagnosed with cancer and agreeing to treatment with its attendant side effects, even though their tumors are slow growing and almost surely not dangerous.
Up to 40 percent of tumors identified through prostate cancer tests fall in this category, according to a separate study published last week in the Journal of the National Cancer Institute.
''There is no question that there are men who are getting the side effects [of prostate cancer treatment] without getting the benefits,'' said Dr. Edward Gelmann, chief of the division of hematology and oncology at Columbia University Medical Center in New York.
The data released Wednesday show that although PSA tests identify more cancers, they don't end up saving more men's lives in the first 10 years of follow-up.
Since that's the case, there's probably no reason for men with life expectancies of less than 10 years to undergo PSA testing, said Dr. Gerald Andriole, lead author of the new study and chief urologic surgeon at Washington University School of Medicine and Barnes-Jewish Hospital in St. Louis.
That includes men over 75 years old, whose expected life span is under a decade, and those with life-limiting conditions such as serious heart disease or poorly controlled diabetes.
Still uncertain is whether screening should be recommended for men in their 50s and 60s who aren't considered at high risk. The data can't answer that question yet because the men haven't been followed for a long enough period.
For those younger men, ''I'm not confident we can say at this point what to do with them,'' Andriole admitted. African-American men and men with a family history of prostate cancer are classified as high risk and should get prostate cancer tests beginning in their 40s, experts say.
Meanwhile, a companion study of about 162,000 men out of Europe, also published online Wednesday by the New England Journal of Medicine, suggests that prostate cancer screening may eventually be shown to save men's lives, the ultimate positive outcome.
Like the U.S. study, it found very little difference in death rates for men who had PSA tests and those who didn't at the 10-year mark. But after that point, evidence of a mortality difference emerged, although the statistical significance of the finding was extremely small.
''I suspect that the differences you start to see at 10 years will widen'' and become even more pronounced 15 and 20 years down the line, said Dr. Charles Brendler, a professor of urology at Northwestern University Feinberg School of Medicine and surgeon at NorthShore University HealthSystem.
However, it's still not clear from the European study whether screening men for prostate cancer achieved more harm than good.
Dr. Otis Brawley, chief medical officer of the American Cancer Society, cites the raw numbers to put the issue in perspective. The European study found that for every 1,410 men who had PSA tests, 48 men were treated for prostate cancer and one death from cancer was prevented.
In other words, ''the chances of harm are 47 times the chance that your life will be saved,'' Brawley said.
No major medical organization in the United States currently recommends routinely screening men for PSA, although several, including the American Cancer Society, suggest that men discuss the issue with their doctors and reach a decision.
Judith Graham is a reporter for the Chicago Tribune, a Tribune Publishing newspaper.