Sep 15, 2010 - 3:32 am
Prostate Screening Fails to Reduce Cancer Cases, Fatalities, Study Finds
The routinely used PSA blood test didn’t reduce the number of cancers or overall deaths, according to a review published today in the British Medical Journal of more than 380,000 men who participated in previous studies.
The study, led by Philipp Dahm of the University of Florida, adds to the evidence that while the PSA blood test detects cancer in its early stages, it doesn’t lead to reduced mortality. The American Cancer Society this year changed its guidelines to reflect the growing uncertainty over testing.
“If we pool together all high-quality studies that exist, rather than picking and choosing evidence, the conclusion is that there is no impact on mortality,” Dahm, an associate professor, said in a telephone interview yesterday.
Dahm’s research used information from six previous studies. While screening raised the chance of being diagnosed with cancer, it didn’t save lives. Finding more tumors early fails to cut deaths in part because prostate cancer grows very slowly, Dahm said.
The study is limited by the fact that it didn’t record the effect on the participant’s quality of life or information on the side effects of screening, Dahm said. The results don’t preclude that a longer follow-up could show some benefit, Dahm said.
Side effects of prostate cancer treatments include incontinence, erectile dysfunction and other complications, according to the National Cancer Institute.
“In addition to the uncertain benefit on mortality, the human and economic costs associated with PSA-based screening are substantial, primarily as a result of overdiagnosis and overtreatment,” Gerald Andriole, chief of urological surgery at the Washington University School of Medicine in St. Louis, said in an accompanying editorial.
Additional research published today found one test at age 60 helped determine future prostate cancer risk. In a study of 1,167 60-year-olds, Hans Lilja of the Memorial Sloan-Kettering Cancer Center in New York found 90 percent of all mortality in men with the highest levels of PSA, while men with low or average levels had negligible rates of prostate cancer or death by age 85.
In its revised guidelines, the American Cancer Society now says men should only be screened if they have been told of the possibility of misleading test results and side effects of treatments that in some cases may pose more harm than the disease itself.
Prostate cancer was the second-most common malignancy in U.S. men last year with 192,280 new cases, and the second- highest killer with 27,360 deaths, according to the society. About half of men who are 50 or older undergo an annual blood test, even after some studies found routine tests don’t increase survival.
Screening for prostate cancer is done by blood tests that measure levels of PSA, or prostate specific antigen, a protein that can increase because of benign prostate conditions or cancer, according to the National Cancer Institute.
To contact the reporter on this story: Eva von Schaper in Munich at firstname.lastname@example.org.