Ethics in Medicine

Prostate Screening Test PSA may not save lives

Kristen Sparrow • March 19, 2009

This particular article is worth reading in its entirety for those interested in the relative value of mass screenings for common diseases. For those of us who don’t always trust the common medical orthodoxy, the conclusion of this article doesn’t come as a huge surprise. I recently attended a symposium offered at UCSF on Issues in Women’s Health. Even I was stunned when one of the presenters was making a case that perhaps even self breast exams over diagnosed breast cancer and exposed the patients to too much medical care which could adversely affect their health. (No snark intended.) Breast cancer has a radically different risk/benefit ratio in terms of screening than PSA, but it is still worthwhile to take a clear-eyed look at the actual numbers of lives saved. Again, it seems that Europe is more likely to lead the way in actually challenging the value of these popular tests and procedures.
(I have not activated the links in my quotations following. If you would like to link to the references, please go to the original article.)
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Prostate Test Found to Save Few Lives
Published: March 18, 2009

“The PSA blood test, used to screen for prostate cancer, saves few lives and leads to risky and unnecessary treatments for large numbers of men, two large studies have found.”…

The studies — one in Europe and the other in the United States — are “some of the most important studies in the history of men’s health,” said Dr. Otis Brawley, the chief medical officer of the American Cancer Society.

In the European study, 48 men were told they had prostate cancer and needlessly treated for it for every man whose death was prevented within a decade after having had a PSA test.

Dr. Peter B. Bach, a physician and epidemiologist at Memorial Sloan-Kettering Cancer Center, says one way to think of the data is to suppose he has a PSA test today. It leads to a biopsy that reveals he has prostate cancer, and he is treated for it. There is a one in 50 chance that, in 2019 or later, he will be spared death from a cancer that would otherwise have killed him. And there is a 49 in 50 chance that he will have been treated unnecessarily for a cancer that was never a threat to his life.

Prostate cancer treatment can result in impotence and incontinence when surgery is used to destroy the prostate, and, at times, painful defecation or chronic diarrhea when the treatment is radiation. …

Vis a vis breast cancer and mammograms:

If the European study is correct, mammography has about the same benefit as the PSA test, said Dr. Michael B. Barry, a prostate cancer researcher at Massachusetts General Hospital who wrote an editorial accompanying the papers. But prostate cancers often are less dangerous than breast cancers, so screening and subsequent therapy can result in more harm... With mammography, about 10 women receive a diagnosis and needless treatment for breast cancer to prevent one death. With both cancers, researchers say they badly need a way to distinguish tumors that would be deadly without treatment from those that would not...

The benefits of prostate cancer screening, he said, are “modest at best and with a greater downside than any other cancer we screen for.”