What's a Guy to Do?
Sunday, March 10, 2002 --- Women having mammograms aren't the only ones getting mixed messages these days. Many men may be surprised to learn that questions have also been raised about whether the standard blood test to screen for prostate cancer does more harm than good. Some of the controversy surrounding the PSA (prostate-specific antigen) test will have a familiar ring to anyone who has followed the mammography debate. But there are also some important differences.
Two trials are under way to determine whether routine PSA tests save lives, but the results will not be in for five or 10 years. Until then, doctors must rely on reports like the study in last week's Canadian Medical Association Journal (CMAJ) in which researchers take a close look at the drop in the death rate from prostate cancer across North America since the mid-1990s. (Read the CMAJ abstract here.)
Supporters of the PSA test contend that the decline is due to the routine screening that began in the 1980s. If that were the case, the researchers from the University of Laval in Quebec City argue, the greatest fall in the death rate would have been recorded in those sections of Quebec where more men underwent screening. In fact, there was no statistical correlation between screening and death rates.
How could this be? For starters, the PSA test, like the mammogram, is a less than perfect cancer detector. Men may develop high PSA levels for many reasons: an infection of the prostate, the natural effects of aging, even bruising caused by a long bicycle ride. Or they may have cancer. Only a biopsy can tell for sure.
So far, so good. Now comes the part that seems illogical. You would think that early detection of cancer would increase a man's chances of being cured and therefore prolong his life. But not all prostate cancers are equally deadly. Indeed, most men, if they live long enough, will eventually develop prostate cancer. But most don't die from it. "Perhaps 10% to 15% of prostate cancers are very benign," says Dr. E. Darracott Vaughan, president of the American Urological Association. "Another 10% to 15% are very aggressive." It's hardest to predict what will happen to the middle 70%.
What's needed is a better way to figure out who will benefit from treatment and who can safely avoid it and its unfortunate side effects, which can include impotence and incontinence. That information may come in the next decade, as we learn more about the genetics of cancer.
In the meantime, if you are a man 50 years or older (40 or older for African Americans), you can start by familiarizing yourself with the pros and cons of PSA tests. After doing so, up to 70% of men decide to get screened. Who knows? The test may still save your life.
For more info, visit cancer.gov or e-mail firstname.lastname@example.org