The blood test millions of men undergo each year to screen for prostate cancer leads to so much unnecessary anxiety, surgery and complications that doctors should stop testing elderly men, and it remains unclear whether the test is worthwhile for younger men, a federal task force concluded Monday.
In the first update of its recommendations for prostate cancer screening in five years, the widely respected panel that sets government policy on preventive medicine said evidence that the test reduces the cancer's death toll is too uncertain to endorse routine use for men at any age, and the potential harms outweigh any benefits for men 75 and older.
“The benefit of screening at this time is uncertain, and if there is a benefit, it's likely to be small,” said Ned Calonge, who chairs the 16-member U.S. Preventive Services Task Force. It published the new guidelines in the Annals of Internal Medicine. “And on the other side the risks are large and dramatic.”
The task force and other groups had concluded previously that it was unclear whether the benefits of the prostate-specific antigen, or PSA, test outweigh the risks. The new review of the scientific literature found no evidence to alter that assessment for younger men but found that enough new data had emerged to recommend for the first time against screening for older men.
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“We felt with sufficient certainty that your risk of being harmed exceeded your potential benefits starting at age 75,” Calonge said.
The guidelines – which address perhaps the most important and contentious issue in men's health – were praised by officials at several leading medical groups, including the National Cancer Institute and the American Cancer Society. But they drew strong criticism from others who are convinced routine screening is necessary.
“I think they're really missing the boat,” said William Catalona, a professor of urology at Northwestern University. “It's a disservice to patients. A lot of men die from prostate cancer, and there's just an overwhelming amount of evidence that screening saves lives.”
More than 218,000 U.S. men are diagnosed with prostate cancer and about 28,000 die of it yearly, making it the most common cancer and second-leading cancer killer of men.
The PSA test, which measures a protein in the blood produced by prostate tissue, has significantly increased the number of men being diagnosed with prostate cancer at very early stages. But it remains unclear whether that translates into a reduction in the death rate from the disease. Prostate cancer often grows so slowly that many men who have the disease die from something else without ever knowing they had it.
Because it is not clear precisely what PSA level signals the presence of cancer, many men experience stressful false alarms that lead to unnecessary surgical biopsies to make a definitive diagnosis, which can be painful and in rare cases can cause serious complications. Even when the test picks up a real cancer, doctors are uncertain what, if anything, men should do about it. Many men simply are monitored closely to see whether the tumor shows signs of growing or spreading. But others undergo surgery, radiation and hormone treatments, which often leave them incontinent, impotent and suffering from other complications.
“People say, ‘What's the harm in screening?' In fact, there are several ways in which screening can actually be harmful,” said Howard Parnes of the National Cancer Institute.
Since the task force's previous recommendations in 2002, at least eight new studies have been published, including a large Swedish study that found that men age 65 and older who were treated for prostate cancer were no more likely to survive than those who were not.
“If therapy isn't providing meaningful benefit, then how could screening provide benefit?” Calonge said.