PSA Screening for Prostate Cancer - Controversy Continues
By Jeffrey Norris | October 18, 2011
A rekindled controversy over the use of PSA screening to help detect prostate cancer highlights the different perspectives physicians may take in framing issues, evaluating studies and deciding on best practices.
Differing perspectives at UCSF include those of a leading urologist, and of an epidemiologist and internist who is a member of the United States Preventive Services Task Force. In its new draft recommendations the task force now says healthy men should not undergo PSA testing.
The task force based its recommendations on a review of reseach studies published Oct. 7 in the Annals of Internal Medicine. The task force concluded that PSA screening saves few lives or none, while the harms are real and significant.
Many physicians may still feel stuck on the horns of a dilemma when it comes to recommending PSA testing, and all wish for a better way to diagnose prostate cancer – and to distinguish life threatening tumors from slow growing ones. The task force will consider public comment before finalizing its recommendations.
UCSF internist and epidemiologist Kirsten Bibbins-Domingo, MD, PhD, is a member of the task force and an author of the recommendation statement. "Unfortunately, the PSA does not distinguish the aggressive cancers that we all want to find and treat from the slow growing ones that may never cause a problem,” she says.
“Treating most men who screen positive as is currently the practice means that many slow-growing cancers are treated, subjecting men to the harms of treatment.”
Because most men with prostate cancer detected as a result of PSA screening have slow growing tumors that are unlikely to cause death, treatment would be unlikely to be life-saving for a majority.
“Nearly one-quarter to one-third of men who are treated have incontinence or impotence,” Bibbins-Domingo says. “Some have more serious complications, including death, without benefit from reduced deaths from cancer."
But deaths due to prostate cancer have declined in recent years, a trend many urologists credit largely to PSA screening and to early detection of life-threatening tumors.
The American Urological Association, which is reviewing its own guidelines, issued a statement disagreeing with the task force. “When interpreted appropriately, the PSA test provides important information in the diagnosis, pre-treatment staging or risk assessment and monitoring of prostate cancer patients,” according to the statement.
UCSF urologist and surgeon Peter Carroll, MD, MPH, director of clinical services for the Helen Diller Family Comprehensive Cancer Center, also values PSA tests, but says results must be evaluated in the context of a man’s age, family history of prostate cancer and ethnicity.