October 2008

Prostate screen may be harmful for older men

According to new recommendations by a government health task force, men aged 75 and older should not be screened for prostate cancer using the prostate-specific antigen (PSA) test, and even many younger men should weigh the risks of the test before taking it. Current data show that one-third of all men in the United States over 75 are receiving PSA testing.

The US Preventive Services Task Force's recommendation and evidence summary appeared this past summer in the Annals of Internal Medicine.

The Task Force found evidence that screening for prostate cancer provided few health benefits but led to substantial physical harms and some psychological harms in men age 75 and older. In men younger than 75, the Task Force concluded that current evidence is insufficient to assess the balance of benefits and harms of prostate cancer screening.

Screening for prostate cancer is most often performed using PSA tests and digital rectal exams. The PSA test is more likely to detect prostate cancer than the digital rectal exam. However, prostate cancers that are found with a PSA test take years to affect health. Most prostate cancers that grow serious enough to cause death take more than a decade to do so. Since a 75-year-old man has an average life expectancy of about 10 years and is more likely to die from other causes such as heart disease or stroke, prostate cancer screening is unlikely to help men over 75 live longer.

For the same reasons, men younger than 75 with chronic medical problems and a life expectancy of fewer than 10 years are also unlikely to benefit from screening. There are also harms associated with prostate cancer screening, which include biopsies, unnecessary treatment and false-positive results that may lead to anxiety.

Complications frequently result from treating prostate cancer and may include urinary incontinence and impotence. These slow-growing cancers may never have affected a patient's health or well-being had they not been detected by screening.

"Because many prostate cancers grow slowly, early detection may not benefit a patient's health and in some cases may even cause harm," said Task Force Chair Ned Calonge, MD, MPH, who is also chief medical officer for the Colorado Department of Public Health and Environment. "We encourage men younger than 75 to discuss with their clinicians the potential -- but uncertain -- benefits and the possible harms of getting the PSA test before they decide to be screened."

SOURCE: Annals of Internal Medicine, August 5, 2008.