Q: Should men get a digital rectal exam (DRE) to check for prostate cancer?
A: Though the DRE is entrenched in U.S. medical practice, its use—like that of the prostate specific antigen (PSA) blood test—is surprisingly controversial. The test involves a doctor or other health care provider inserting a gloved, lubricated finger into the rectum to feel for bumps or other growths on the prostate gland. It is commonly done as part of a routine physical exam, especially in men over 50.
Many researchers and medical practitioners believe that the DRE remains an important part of prostate cancer screening, based on study findings and clinical experience. In a study in the Canadian Journal of Urology in 2012, for example, the DRE found many prostate cancers that a PSA test did not. Of 306 men with biopsy-confirmed cancer, 136 had an abnormal DRE finding—and of those, 43 had a normal age-adjusted PSA. That means that the PSA test alone, without the DRE, would have missed 31 percent of the cancers.
On the other hand, neither the U.S. Preventive Services Task Force nor the American College of Preventive Medicine recommends routine DRE (or PSA testing) for prostate cancer screening, citing insufficient evidence of benefit and possible harms. For one, it’s unclear whether men who are screened with DRE have a reduced risk of dying from prostate cancer. In general, the results depend on the expertise of the practitioner, and, like the PSA test, the DRE has a high rate of false positives—that is, something suspicious may be felt that turns out to be noncancerous upon follow-up testing. Or it can miss cancers, particularly those on the front and top of the prostate gland, areas that are beyond reach.
Still, there are other reasons to have the DRE. It’s frequently done in both men and women, for example, to check for masses in the rectum, since rectal cancer can often be detected on digital examination before it becomes symptomatic or sheds blood— though the DRE is not a substitute for colorectal cancer screening with colonoscopy, sigmoidoscopy or stool tests.