“The evidence suggests that in most cases, it is time to abandon the digital rectal exam (DRE),” said Ryan Terlecki, M.D., a Wake Forest Baptist urologist who recently published an article on the topic in Current Medical Research and Opinion. “Our findings will likely be welcomed by patients and doctors alike.”
Terlecki said the DRE, referred to by some urologists as a “clinical relic,” subjects a large number of men to invasive, potentially uncomfortable examinations for relatively minimal gain. In addition, it may deter some men from undergoing any test for prostate cancer.
The issue Terlecki’s team explored was whether the DRE is needed when another more accurate test that measures prostate-specific antigen (PSA) in the blood is available. PSA is a protein that is often elevated in men with prostate cancer.
“Many practitioners continue to perform DRE in attempts to identify men with aggressive prostate cancer who could die from the disease,” said Terlecki. “In the era of PSA testing, we wanted to explore whether it’s time to abandon the digital exam.”
To reach their conclusion, Terlecki’s research team reviewed both medical literature and the results of a nationwide screening trial in which 38,340 men received annual DRE exams and PSA tests for three years. They were then followed for up to 13 years.
Of interest to Terlecki’s team were the 5,064 men who had a normal PSA test but an “abnormal” DRE. Only 2 percent of these men had what is known as clinically relevant prostate cancer, which means it may need to be monitored or treated.
“The DRE does capture an additional small population of men with significant prostate cancer, but it also unnecessarily subjects a large number of men to the test,” he said.
Until 2012, men over 50 (age 40 for African-Americans) were urged to have both DRE and PSA tests annually. That was before the United States Preventive Services Task Forces recommended against routine PSA testing because it could lead to over-treatment of slow-growing, non-harmful tumors. The panel did not address DRE, which was the primary method of detecting prostate cancer prior to the blood test.
As a result of the task force’s recommendation, there has been confusion and controversy about whether men should be screened for prostate cancer. Some organizations recommend against any screening and others recommend PSA screening, but only if men are counseled about the potential benefits and risks.
In previous studies, PSA had been shown to outperform DRE in detecting significant disease. The current analysis confirmed that PSA is superior to DRE as an independent screen for prostate cancer. PSA testing detected 680 cases of significant cancer, compared to 317 cases for DRE.
“When PSA testing is used, the DRE rarely assists in diagnosing significant disease,” said Terlecki. “In cases where PSA testing is used, the DRE should be abandoned in common clinical practice.”
There is still a place for DRE testing for certain patients, Terlecki said. For example, a patient with abnormal PSA who is “on the fence” about having a biopsy, may feel more comfortable proceeding with the procedure if a DRE is also abnormal, he said.