In a move that could lead to significant changes in medical care for older men, a national task force recommended yesterday that doctors stop screening men 75 and older for prostate cancer because the search for the disease in this group is doing more harm than good.
The new guidelines, issued by the U.S. Preventive Services Task Force, represent an abrupt policy change by an influential panel that had withheld any advice regarding screening for prostate cancer, citing a lack of reliable evidence. Though the task force still has not taken a stand on the value of screening in younger men, the shift is certain to reignite the debate about the appropriateness of prostate cancer screening at any age.
Screening for prostate cancer is typically performed with a blood test measuring prostate-specific antigen, or PSA, levels. Widespread PSA testing has led to high rates of prostate cancer detection. Last year, more than 218,000 men were diagnosed with the disease.
Yet various studies suggest the disease is "over-diagnosed" - that is, detected at a point when the disease probably would not affect life expectancy - in 29 percent to 44 percent of cases. Prostate cancer often progresses very slowly, and a large number of these cancers discovered through screening probably will never cause symptoms during the patient's lifetime, particularly if that patient is older. At the same time, aggressive treatment of prostate cancer can greatly reduce a patient's quality of life, resulting in such complications as impotency and incontinence.
Past task force guidelines noted there is no benefit to prostate cancer screening in men with fewer than 10 years left to live. Since it can be difficult to assess life expectancy, it was an informal recommendation that had limited impact on screening practices. The new guidelines take a more definitive stand, stating that the age of 75 is clearly the point at which screening is no longer appropriate.
The task force was created by Congress to analyze current medical research and to make recommendations about preventive care for healthy people. Its guidelines are viewed as highly credible and often are relied on by practicing physicians in making decisions about patient care.
"When you look at screening, you have a chance the screening will help you live longer or better, and you have the chance that screening detection and treatment will harm you," said Dr. Ned Calonge, chairman of the task force and chief medical officer for the Colorado Department of Public Health and Environment. "At age 75, the chances are great that you'll have negative impacts from the screening."
It is estimated that one of every three men 75 and older is now screened for prostate cancer, although some studies suggest the number is even higher. The Journal of the American Medical Association reported in 2006 that in a group of nearly 600,000 elderly men treated by the Department of Veterans Affairs, 56 percent of those ages 75 to 79 were screened for prostate cancer. Given the large numbers of men over age 75 who currently are being screened, even a small decline in testing might greatly reduce the number of new prostate cancer cases.
Calonge said it was important that the guidelines not be viewed as "giving up" on older men. While the new rules should discourage routine testing of older patients, the recommendations won't prevent a man from seeking screening if he desires it, Calonge said. The new guidelines are not expected to alter Medicare's current reimbursement for annual PSA screening of older men.
The guidelines focus on the screening of healthy older men without symptoms and will not affect treatment of men who go to the doctor with symptoms of prostate cancer.
Studies of the value of prostate cancer screening for younger men have produced mixed results, but a major clinical trial under way in Europe will attempt to determine whether there is any value, in terms of longer life expectancy, to screening of this group for prostate cancer. Those results might be published as early as next year.
While the verdict is still out on younger men, the data for older men are more conclusive, experts say. The American Cancer Society and American Urological Association both say annual PSA screening should be offered to average-risk men 50 and older, but only if they have a greater-than-10-year life expectancy.