Time to Abandon the Digital Rectal Exam?

Fran Lowry

September 15, 2016

In men with a normal prostate specific antigen (PSA) level, the digital rectal examination (DRE) rarely assists in diagnosing clinically significant prostate cancer, yet it is an invasive, uncomfortable examination with very little gain, according to a new study.

In an analysis of data from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO), DRE screening in the setting of normal PSA levels captured an additional 2% of men with clinically significant prostate cancer.

It may be time to abandon the DRE, suggest the authors of an article published in Current Medical Research and Opinion.

"A lot of men will comment that they are dreading the visit because they fear the digital rectal exam, so through conversation with patients and also through the literature, we recognized that the thought of the DRE keeps some men from coming to our office," author Ryan P. Terlecki, MD, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina, told Medscape Medical News.

Dr Ryan Terlecki

In 2012, the United States Preventive Services Task Force (USPSTF) released recommendations against routine PSA screening for prostate cancer in healthy men.

The recommendation was controversial, but physicians did reduce routine PSA screening. However, there has been less focus on DRE screening, and it has been unclear whether DREs improve cancer detection, Dr Terlecki said.

He and his team decided to look at how useful DRE screening was in the PLCO trial.

The nationwide, population-based trial evaluated cancer screening programs and their impact on cancer mortality. In the screening arm, 38,340 men received annual PSA testing and DREs during the first 3 years; they continued to undergo PSA for screening an additional 2 years, for a total of 5 years. The control arm consisted of patients who received usual care. Participants were followed for up to 13 years.

Those with an abnormal test result were referred to their individual healthcare provider for biopsy.

Dr Terlecki and his group focused on the men who received both screening tests in the first 3 years.

Using National Comprehensive Cancer Network prostate cancer guidelines, the researchers defined a clinically significant prostate cancer as a tumor associated with PSA level > 10 ng/ml, a Gleason score ≥7, or clinical stage ≥T2b in men aged 75 years or younger.

During that time, the men received 129,028 PSA tests and 124,694 DREs.

Of PSA tests, 10,490 (8.1%) were abnormal and resulted in 3422 (32.6% of abnormal screens) biopsies.

Those biopsies identified 1317 men with prostate cancer; of these cases, 680 (19.9%) were considered to be clinically significant prostate cancer.

Of the DRE tests, 9362 (7.5%) were abnormal and were suspicious for prostate cancer; these tests led to the performance of 2024 biopsies.

For each year studied, men with isolated abnormal DREs were significantly (P < .05) less likely to undergo biopsy than those with isolated abnormal PSA levels.

The biopsies that were triggered by an isolated abnormal DRE result identified 616 men with prostate cancer, and of those, 317 men were considered to have clinically significant prostate cancer.

The analysis showed that the rate of prostate cancer detection with DRE was significantly lower than that associated with isolated abnormal PSA results for each year and overall (P < .01), with the exception for year 2 (P = .12).

Maximal Pain, Minimal Gain

"Our analysis reemphasizes the superiority of PSA as an independent screen for prostate cancer that is clinically significant, compared to DRE," Dr Terlecki said.

"An abnormal PSA led to the detection of 680 cases of clinically significant prostate cancer, compared to 317 cases from an abnormal DRE, and most of those, 69%, also had an abnormal PSA. So the digital rectal exam did not appear to be useful in detecting cases of clinically significant disease if men were going to have PSA anyway," he said.

"This is interesting, because a lot of people don't realize, urologists especially, that our governing association, the American Urological Association, states that there is no evidence that the digital rectal exam is beneficial and that it should not be in primary screening, but that it could potentially be useful as a secondary test in men who have elevated PSA," Dr Terlecki said.

"Also, the American Cancer Society continues to recommend PSA but doesn't require the rectal exam," he said.

The PLCO data also showed that one would have to perform well over 1000 DREs to find one case of significant prostate cancer, Dr Terlecki said.

"The data did suggest that if both PSA and digital rectal exam were both abnormal, there may be a higher chance of significant prostate cancer, but if you are going to biopsy someone on the basis of an abnormal blood test anyway, doing the digital rectal exam seems not to add anything," he said.

However, Dr Terlecki did note that the conclusions from his study are based on data derived from the PLCO study. That study has been criticized for a number of factors; these include inconsistent use of biopsy following positive screening tests, lack of end-of-study biopsies to determine population disease burden, and low numbers of black men in the study.

The Thought of the DRE Keeps Some Men From Screening

"We are not challenging screening at all. We're just talking about the digital rectal exam. For those who are in favor of screening, our report might be a welcome addition to the literature, because it has already been shown that the DRE is a barrier for men to actually participate in screening," Dr Terlecki said.

"For example, a little over 40% of African American men reported fears of discomfort and embarrassment from the exam in one study," he said.

"The DRE isn't even useful to evaluate for an enlarged prostate, rectal tone in trauma cases, and things of this sort, as we found when we searched the literature. It used to be used for screening for colon cancer, but as of 2002, the USPSTF no longer advocates its use for that either," Dr Terlecki said.

He added: "If somebody already has diagnosed prostate cancer and is being treated with radiation or certain types of surgery, that is a different story, and this study was not designed to challenge that. But if we think about the DRE in terms of screening and looking for an initial problem, I don't really see a role. Overall, I think that this most common clinical examination for me, the digital rectal exam, should be largely abandoned, based on the evidence before us."

Dr Terlicki continued: "Traditionally it was just something that the doctor would do, like a knee jerk reaction, during a routine physical, and it is such an uncomfortable part of the exam for most men. So if it's not providing useful information, why go through it?"

Don't Abandon the DRE

However, some researchers disagree.

As reported in Medscape Medical News, once a man decides to undergo screening for prostate cancer, then both PSA testing and the DRE should be carried out, according to David Penson, MD, MPH, chair of the Department of Urologic Surgery at Vanderbilt University Medical Center, Nashville, Tennessee.

The Medscape article mentions a patient who was diagnosed after an internist felt what he described as a hard nodule in the prostate during a DRE, despite the patient's having a low PSA level.

Asked to comment on this study by Medscape Medical News, Marc B. Garnick, MD, Beth Israel Deaconess Medical Center and Gorman Brothers Professor of Medicine at Harvard Medical School, Boston, Massachusetts, warned: "Family and primary care physicians should not mistakenly interpret the results of this study by endorsing the elimination of performing DREs."

Dr Garnick said that the arguments that the authors make for discontinuing use of the DRE as a method of screening for prostate cancer are "compelling."

 
My personal practice will never abandon DRE. Dr Marc Garnick
 

"Their data, as well as earlier data, suggest limited utility of DRE alone as a screening modality for prostate cancer, regardless of whether it is indolent or clinically significant. However, my personal practice will never abandon DRE as an integral part of the physical examination beyond screening considerations," he said.

"It is an important portion of the exam for men with urinary symptoms. Does my examination suggest BPH [benign prostatic hyperplasia] or something more nefarious? There are other anatomic considerations evaluated during a DRE, for instance, the distal rectum and anus," Dr Garnick said.

"In following patients with a rising PSA post radical prostatectomy, DRE can be extremely helpful in identifying anastomotic or local recurrences. For those who have an elevation in PSA post radiation, DRE is helpful in post radiation treatment considerations," he said.

"Finally, appreciate that in the current study, of all of the men with abnormal DREs, only a small proportion underwent biopsy, hence weakening the otherwise cogent arguments made by the authors. And even if there is less evidence-based information about DRE utility for screening for prostate cancer, there are a multitude of other reasons for continuing to keep it as an integral part of the physical examination," Dr Garnick said.

Weighing in with his opinion, J. Brantley Thrasher, MD, William L. Valk Distinguished Professor, Department of Urology, University of Kansas Medical Center, Kansas City, told Medscape Medical News he would not abandon the DRE.

"Given the limitations of this study, as mentioned by the authors, and the fact that DRE is a relatively benign exam with very few, if any, complications, I would continue to offer DRE as a part of screening," Dr Thrasher said.

"Additionally, more information from diverse populations should be available before I will abandon this simple and safe exam. I have found numerous abnormalities in the face of normal PSAs over the years," he said.

Dr Terlecki, Dr Garnick, and Dr Thrasher report no relevant financial relationships.

Curr Med Res Op. Published online July 4, 2016. Abstract

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