Prostate Cancer Screening Found to Save Few, if Any, Lives

Courtesy of The New York Times

The PSA blood test — the screening test for prostate cancer — saves few if any lives and exposes large numbers of men to risky and unnecessary treatment, two large and rigorous studies have found. The findings raise new questions about the rapid and widespread adoption of the test, which measures a protein released by prostate cells. It was introduced in 1987 and quickly became a routine part of preventive health care. Experts debated its value, basing their views on data that often involved statistical modeling and inferences. Now, with the new data, cancer experts said men should carefully consider the test’s risks and benefits before deciding to be screened.

Some may decide not to be screened at all. The studies, said Dr. Otis Brawley, the chief medical officer at the American Cancer Society, are “some of the most important studies in the history of men’s health.” For years, the cancer society has urged men to be informed before deciding to have a PSA test. “Now we actually have something to inform them with,” he said. “We’ve got numbers.” Dr. H. Gilbert Welch, a professor of medicine at Dartmouth who studies cancer screening, also welcomed the new data. “We’ve been waiting years for this,” he said. “It’s a shame we didn’t have it 20 years ago.”

Both reports were published online on Wednesday by The New England Journal of Medicine. One involved 182,000 men in seven European countries; the other, by the National Cancer Institute, involved nearly 77,000 men at 10 medical centers in the United States. In both, participants were randomly assigned to be screened — or not — with the PSA test, whose initials stand for prostate-specific antigen. In each study, the two groups were followed for more than a decade while researchers counted deaths from prostate cancer, asking whether screening made a difference. The European data involved a consortium of studies with different designs.

Taken together, the studies found that screening was associated with a 20 percent relative reduction in the prostate cancer death rate. But the number of lives saved was small — seven fewer prostate cancer deaths for every 10,000 men screened and followed for nine years.

The American study, which had a single design, found no reduction in deaths from prostate cancer after most of the men had been followed for 10 years. Every man has been followed for at least seven years, said Dr. Barnett Kramer, a study co-author at the National Institutes of Health. By seven years, the death rate was 13 percent lower for the unscreened group. The European study saw no benefit of screening in the first seven years of follow-up.

The reason screening saved so few lives, cancer experts say, is that prostate cancers often grow very slowly, if at all, and most never endanger a man if left alone. But when doctors find an early-stage prostate tumor, they cannot tell with confidence whether it will be dangerous so they usually treat all early cancers as if they were life-threatening. As a result, the majority of men, whose early-stage cancers would not harm them, suffer serious effects of cancer therapy but get no benefit. Others, with very aggressive tumors, may not be helped by screening because their cancer has spread by the time it is detected.

In the European study, 48 men were told they had prostate cancer, and needlessly treated for it, for every man whose death was prevented. 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 or health.

Prostate cancer treatment can result in impotence and incontinence when surgery is used to destroy the prostate, and painful defecation or chronic diarrhea when the treatment is radiation. When the American and European studies began, in the early 1990s, PSA testing was well under way in the United States, and many expected that the screening test would make the prostate cancer death rate plummet by 50 percent or more.

In the meantime, Dr. Brawley said, “I certainly think there’s information here that’s food for thought.” The benefits of prostate cancer screening, he said, are “modest at best and with a greater downside than any other cancer we screen for.”

Bonnie - this is so sad and frustrating to read. I have had countless male clients who received unnecessary procedures because of high PSA's. If you have read my blogs and eNewsletters, you know that I have been very wary of PSA's since the beginning. This is yet another example of "putting the cart ahead of the horse." Billions of dollars in medical procedures and who knows how many life-impaired males later, we are left with a screening "with a greater downside than any other cancer we screen for."