Little Evidence Supports Use of Digital Rectal Exam

Ricki Lewis, PhD

March 13, 2018

Digital rectal examination (DRE) inadequately identifies risk for prostate cancer on a population level, according to a meta-analysis that compared DRE indications of elevated risk with biopsy outcomes.

DRE and prostate-specific antigen measurement form the basis of population screening for elevated risk for prostate cancer. Both procedures may be part of a well-care visit to a primary care provider.

Studies have suggested DREs are associated with a high rate of false-positives and no reduction in prostate cancer mortality, while subjecting patients to unnecessary and invasive follow-up procedures and perhaps overdiagnosis and overtreatment of prostate cancer. Despite questions about DRE benefits, a recent survey found that 81.0% of primary care physicians in Canada report using it in their clinics.

Therefore, to better understand the effect of DRE, Leen Naji, MD, from the Department of Family Medicine at McMaster University in Hamilton, Ontario, and colleagues conducted a systematic review and meta-analysis of the diagnostic accuracy of DRE administered in the primary care setting as a screen for prostate cancer.

Naji and colleagues searched several databases for the terms "prostate cancer," "digital rectal examination," and "biopsy" in studies and systematic reviews that evaluated the effectiveness of DRE in screening for prostate cancer by primary care clinicians.

Their meta-analysis, published in the March/April issue of the Annals of Family Medicine, included 7 studies that enrolled a total of 9241 patients who underwent DRE. Diagnosis of prostate cancer was based on prostate biopsy.

The sensitivity of the pooled studies for DRE was 0.51 (95% confidence interval [CI], 0.36-0.67), and specificity was 0.59 (95% CI, 0.41-0.76). The pooled positive predictive value was 0.41 (95% CI, 0.31-0.52), and the pooled negative predictive value was 0.64 (95% CI, 0.58-0.70).

The investigators conclude that DRE as performed by primary care providers does not meet the World Health Organization criterion of benefits of a screening test outweighing harms.

"On the basis of the lack of evidence supporting its use, we do not recommend routinely using DRE as a screening tool for prostate cancer in primary care, unless it is proven effective in future studies. Additionally, although we did not study possible harms of DRE, its invasiveness and potential to lead to unnecessary biopsy, overdiagnosis, and overtreatment argue against its routine use," the researchers conclude.

Limitations of the meta-analysis include the variability of the studies, in terms of who actually performed the DREs; absence of an accepted universal definition of abnormal DRE; and the lack of controls. In addition, the false-negative rate could not be ascertained because men with negative results didn't progress to biopsy.

The researchers have disclosed no relevant financial relationships.

Ann Fam Med. 2018;16:149-154. Abstract

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