The evidence has long been shaky on the benefits of the PSA screening test for prostate cancer, so it should have been little surprise when the U.S. Preventive Services Task Force, a group of primary care doctors that advises the Department of Health and Human Services, downgraded its rating of the test from I (for insufficient evidence) to D (evidence that there is no benefit) for men without symptoms of disease.
The experts had done a comprehensive review of the evidence, including a new, big study, and concluded it was not worthwhile to use the blood test for regular screening of most men over 40.
Nonetheless, there was still an outcry. The controversy about such scientific analysis shows just how hard it will be to nudge our medical system in the direction of evidence-based practice.
ZERO, a prostate cancer patient group committed to improving early detection of the disease, immediately released a statement expressing its outrage on the panel’s scientific judgment. “Today's decision of no confidence on the PSA test by the U.S. government condemns tens of thousands of men to die this year and every year going forward,” Skip Lockwood, the group’s CEO, said in a statement.
Urologists, the specialists who most frequently treat the disease, also weighed in, saying that the guidelines would discourage men in high-risk groups from getting needed tests.
The panel, whose findings are advisory, examined several large, long-term studies that compared men with no symproms who got the screening test with men who were not regularly screened. What they found was that the screened men did not live longer, but they were still diagnosed and treated for prostate cancer at much higher rates.
“The common perception that PSA-based early detection of prostate cancer prolongs lives is not supported by the scientific evidence,” the report said. Because prostate cancer treatment carries high risks of impotence and urinary incontinence, among other complications, the panel determined that more men were being hurt than helped by the test.
The task force did not consider cost in its evaluation, but the widespread screening, diagnosis, and treatment of prostate cancer is hugely expensive to the medical system. According to the American Cancer Society, about 240,000 men are diagnosed with the disease every year and 34,000 die of it. About 90 percent of men who are diagnosed are treated with radiation, surgery, or drugs. But the task force’s evidence review found that there was no evidence that PSA screening saved lives overall.
The PSA test looks for a prostate specific antigen, a compound made only by prostate cells. The more active the prostate -- such as when it's growing or inflamed -- the more PSA it makes. So a rise in PSA could indicate either cancer or a natural enlargement of the prostate gland that occurs in many men with age.
What the research has found is that prostate cancer is so slow-growing in most men that men who are not tested for the chemical often die with prostate cancer, but not from it. There is still no good test that distinguishes between the slow growing tumors and those likely to spread and cause disease.
Still, many urologists believe that discouraging PSA testing will cause needless deaths and sickness for many men.
“Before we had PSA testing, we used to have clinics filled with people who were alive, who died of a heart attack or a stroke, but had terrible quality of life because they had diffuse prostate cancer,” said Dr. Thomas Jarrett, a professor and Chairman of Urology at George Washington University Hospital in Washington, D.C. Jarrett was diagnosed and treated for prostate cancer at 46, after beginning annual screening at 40.
Jarrett had a family history of the disease, and he, along with the American Urological Society, expressed particular concern that African-American men and men whose family members had been diagnosed still need to be tested. The task force’s report said those groups have been studied in smaller numbers than the general population, but there is no evidence, so far, that such men benefit from testing.
Current recommendations about when and how often men should be screened vary. The American Cancer Society suggests men at normal risk should discuss the benefits and risks of testing beginning at age 50, and men in risk groups should begin talking to their doctors at 45. The American College of Physicians and the American College of Preventive Medicine suggest discussions between men and their doctors starting at 50. The American Urological Society suggests a baseline screening test at 40, annual screening in all men beginning at 50, and annual screening after 40 for men in known risk groups.
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