Prostate testing challenged

September 14, 1994|By Jonathan Bor | Jonathan Bor,Sun Staff Writer

A week away from a national campaign of free prostate exams, a study in a leading medical journal has whipped up controversy by concluding that screening healthy men for the potentially deadly cancer does little good.

While they agreed that yearly blood tests and digital exams are capable of detecting prostate cancers before they spread, researchers writing in today's Journal of the American Medical Association said that surgical treatments for early cancers only marginally extend life.

And when they weighed the occasional pitfalls of surgery, which can include incontinence and impotence, researchers said that there is no reason to recommend annual screenings that have become a virtual mantra of the American Cancer Society and other health organizations.

"I wouldn't screen myself," said Dr. Allan S. Detsky, a clinical epidemiologist from the University of Toronto Medical Center who participated in the study. "Why would I want to find the answer to something that I don't know what to do about?"

The study, based on a complicated computer model, was done by researchers at the University of Toronto Medical Center and affiliated hospitals in Toronto, as well as the Tufts University School of Medicine in Boston.

Yesterday, the article drew a sharp rebuke from urologists at Johns Hopkins Hospital and the University of Maryland Medical Center, as well a top official of the American Cancer Society. They said the researchers fed their computer with flawed data that caused it to yield the wrong conclusions to the question of screening.

"I think it's a terrible study," said Dr. Patrick Walsh, director of urology at the Johns Hopkins School of Medicine, adding that he complained to one of the study's authors and to its editor at JAMA. "Let's face it, next week is Prostate Cancer Awareness Week. Is it a coincidence that it's coming out a week before?"

A spokesman for the American Medical Association, which publishes the journal, said the article's timing was pure coincidence.

Next week, 800 medical centers across the country will offer free and low-cost cancer tests in a program sponsored by the Prostate Cancer Education Council, headquartered at the University of Colorado. It is expected to be one of the largest campaigns of its kind.

In Baltimore, free rectal exams and blood tests -- called the prostate specific antigen or PSA test -- will be offered Monday through Wednesday at the Johns Hopkins Bayview Medical Center.

Critics said the Toronto-based study exaggerated the side-effects of prostate surgery and was skewed by the fact that it analyzed the benefits of a one-time screening rather than a series of annual tests.

While a single test is likely to detect an advanced cancer -- the type that rarely responds to treatment -- repeat screens are more likely to flag smaller and more treatable cancers as they develop, they said. "No one would require a PSA screening to be done once," Dr. Walsh said.

"A lot of people have poor outcomes because they've never been screened before," said Dr. Michael Naslund, director of the Maryland Prostate Center at the University of Maryland Medical Center. "A lot will have cancer at a late stage. But if some of them had been screened three years earlier, they might have been caught at an earlier stage and cured."

Prostate cancer is a malignant growth in the prostate gland, an organ that produces secretions that are part of seminal fluid. The Cancer Society estimates that 200,000 new cases will be diagnosed in the United States this year; 84,000 men will die of the disease, making it the second leading cancer killer among men.

The Cancer Society recommends annual screenings for all men over the age of 50.

Although screening tests can detect cancer early, researchers have yet to settle the question of whether early treatment actually extends life. For today's published study, researchers compared the likely benefits and drawbacks of screening healthy men to doing nothing at all. To do this, they had a computer analyze such data as the accuracy of tests, the probability of finding disease and the likelihood of living various lengths of time after treatment.

Screening all men between the ages of 50 and 70 would cost about $12 billion in a single year, the researchers said. They conceded, however, that the full figure does not represent added costs, since many men already get screened.

The researchers found that one-time tests would increase the life span of all men who are screened by less than one day for a 50-year-old man and 1.7 days for a 70-year-old. When they subtracted time for "poor quality of life" from incontinence or impotence after surgery, researchers concluded that men actually had a net loss of three to 13 days.

Dr. Walsh, however, said the study should have measured the survival time of men treated for prostate cancer -- not the survival time averaged among all men who were screened, whether or not they had cancer.

The best data, he said, indicate that men treated for early cancers live an average of 2 1/2 years longer than those not treated.

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