July 2, 2010
New Evidence Supports Prostate Cancer Screening
My regular readers know that prostate cancer screening has been an active research topic recently. (My not-so-regular readers who are interested are invited to catch up on the topic by reading my most recent post on the subject. See the link below.) Whether testing men for prostate cancer saves lives is still an open question. Large trials are currently underway that should provide a definitive answer in the next few years.
In the meantime, preliminary results from a Swedish trial give prostate screening a boost. The study, published in The Lancet, randomized 20,000 men between 50 and 64 years of age to a group that was invited to undergo PSA testing every 2 years, and another group that was not. The men in the screening group were offered PSA tests until they reached age 70. Men with elevated PSAs were offered further testing such as digital rectal examinations and prostate biopsies.
As expected, more prostate cancer was diagnosed in the screening group than in the control group. 12.7% of the men in the screening group were diagnosed with prostate cancer compared to 8.2% in the control group. Also as expected, the mortality rate from prostate cancer was quite low, as prostate cancer typically grows quite slowly and takes many years to cause harm. Nevertheless, the screening group showed a survival advantage. The risk of death from prostate cancer was 0.90% for the control group and only 0.50% in the screening group.
This means that (at least in this study) screening for prostate cancer saved lives. For each life saved, 293 men needed to be invited for screening and followed for an average of 14 years and 12 men were diagnosed with prostate cancer. Similar to mammography screening for breast cancer, the vast majority of people screened were not helped, and some were certainly harmed by surgery for cancer that would not have shortened their lives. Others died of prostate cancer despite being screened.
This is the first glimmer suggesting that routine PSAs may indeed be life-saving, with benefits in the same numerical ball-park as mammograms for breast cancer. Definitive answers are expected in the next few years as larger studies are completed.
Wall Street Journal Health Blog post: Swedish Trial Finds Prostate-Cancer Screening Saves Lives
My last post about prostate cancer screening: American Cancer Society Revises its Guidelines for Prostate Cancer Screening
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