Men Want Prostate Screening...
... Even though there's no proof it saves lives
THURSDAY, Oct. 3, 2002 (HealthDayNews) -- Most men would gladly recommend prostate cancer screening to their friends and sons -- even when they know there's no proof the test saves lives.
A survey published this week in the British Medical Journal of 52 United Kingdom men who underwent blood screening for prostate cancer -- called a PSA test -- found that 48 said they'd encourage other men to do the same. Only four demurred. They cited a lack of evidence that PSA testing, which can potentially lead to invasive treatment with serious side effects, reduces the risk of dying from the tumors.
In fact, the skeptics are correct. Another study in the journal found that aggressive PSA screening and tissue sampling in suspicious cases greatly increased the odds that men would undergo prostate-removal surgery and radiation treatments for cancer.
However, that didn't lower their risk of dying from the disease.
"There's an awful lot of confusion about prostate cancer screening, with certainly no good evidence that it decreases mortality," says Ann McPherson, a research lecturer at the University of Oxford and a co-author of the study.
PSA, or prostate specific antigen, is a protein used both as a screening tool and as a way to measure the progress of the disease. This molecule is found normally in men throughout the body, but is produced in mass quantities by prostate tumors.
Routine PSA testing is not recommended in the United States or Britain. But men over age 50 in the United States are given the option of regular screening while in the United Kingdom, they get the test only when their doctor suspects prostate cancer. As a result, American men who opt for PSA screening inherently believe it could save their life, McPherson says.
Of the 48 British men who opted for the test, many were willing to overlook the lack of evidence that it would prolong their life. Overriding concerns, they said, were acting responsibly, having a right to one's own health information and avoiding possible regrets for not taking the test.
Prostate cancer is the number two cancer killer of men in the United States, affecting 190,000 and killing more than 30,000 each year. Death rates from the disease have been falling for the last five years, a decline some doctors attribute to PSA testing.
However, if the test is indeed saving lives, areas with more aggressive screening programs should see lower mortality rates from prostate cancer, says Dr. Michael Barry, chief of general medicine at Massachusetts General Hospital and a co-author of the second journal article.
To test that hypothesis, Barry and his colleagues turned to Washington and Connecticut, two states with much different approaches to prostate cancer screening. They followed 94,000 Seattle Medicare recipients and 120,000 Connecticut recipients between 1987 and 1997.
During the early years of the study, the Washington men underwent the test more than five times as frequently as those on the East Coast, and they had more than double the rate of biopsies to probe suspect prostate glands.
Not surprisingly, the aggressive screening program uncovered many more cases of cancer. "The more you look for it, the more you find," Barry says.
For the first three years of the study, the age-adjusted incidence of the disease was 83 percent higher in Seattle than it was in Connecticut, though that difference dropped to 11 percent for the years 1991 through 1996.
As a result, the rates of prostate removal surgery and radiation to shrink the gland were sharply higher in Washington -- 2.7 percent and 3.9 percent, respectively, versus 0.5 percent and 3.1 percent in Connecticut.
However, while mortality rates from the disease dropped in both areas, by the end of the study the two groups of men had equal odds of dying from prostate cancer.
"It didn't look like the much more aggressive approach in prostate screening reduced mortality," Barry says.
The study focused on men aged 65 to 79, and it's possible that younger men might benefit more from screening, Barry says. Another caveat is the possibility that men in Washington have different risk factors for prostate cancer than those in Connecticut, which could influence the results of the study.
However, the latest findings don't bode well for supporters of the PSA test, says Dr. Theodore Ganiats, a family physician at the University of California, San Diego.
The National Institutes of Health is sponsoring a large, randomized trial of PSA testing. Ganiats, who helped write the PSA screening guidelines for the American Academy of Family Physicians, which doesn't recommend routine testing, says the results of the trial should help settle the controversy.
In the meantime, he says he tells his patients that the choice to have the test is theirs to make. "In the absence of good data, it's whichever way you feel you're going to sleep better tonight," Ganiats says.
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