COMMENTARY

Digital Rectal Exam's Role Increasingly Unclear in Detecting Early Prostate Cancer

Gerald Chodak, MD

Disclosures

October 24, 2016

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Hello. I'm Dr Gerald Chodak for Medscape. Today I want to talk about whether the digital rectal exam should be included as part of a routine exam screening for prostate cancer.

Cui and coworkers[1] have written a paper in which they analyzed data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Screening Trial. In that trial, over 38,000 men were enrolled, and more than 5000 had an abnormal digital rectal exam when their prostate-specific antigen (PSA) was in the low range—that is, not suspicious for cancer. Of those men who had an abnormal rectal exam, 2% were diagnosed with intermediate- or high-risk prostate cancer, meaning that a very high percentage of men were subjected to a biopsy with no chance of having cancer.

Based on this low detection rate with the digital rectal exam, what should be done? The study's authors questioned whether the digital rectal exam is no longer a useful test. Many people have argued that at least for the diagnosis of colorectal cancer, the digital rectal exam is an important part of testing. However, the US Preventive Services Task Force does not include the digital rectal exam among its recommendations for routine colorectal cancer screening at this time.[2] So that argument seems to have gone away.

One could question whether those men who had cancer diagnosed when their rectal exam was abnormal, but their PSA was normal, would have been diagnosed at a later date with serial PSA tests had routine screening been continued. The overall net benefit from routine testing is therefore unclear. It's important to point out that no randomized study has ever proven that a digital rectal exam saves lives. In fact, in the European trial that allegedly has shown a benefit from PSA screening, digital rectal exam was not part of the routine exam.[3,4]

Where does that leave us today? Should the digital rectal exam be abandoned? We know that many men don't like having it done, and I expect that many doctors don't like performing the test.

The Prostate Cancer InfoLink website has made what seems to be the most sensible suggestion: It should be part of the discussion with patients, telling them that the test can help find a cancer even if your PSA is normal. You and your patients can make a decision jointly about whether the PSA should be done in the first place. And if the test is not done, the rectal exam certainly can be offered and discussed as one way to help find a cancer. For now, it seems that is the most sensible way to go, and whether it will continue in the future remains unclear.

This whole controversy about screening is still not fully evaluated or determined, and I expect that more information is going to come forth. But for now, it's reasonable to question whether the digital rectal exam truly serves a purpose in helping find early prostate cancer.

I look forward to your comments. Thank you.

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