Screening and assessing for prostate cancer (PCa) is a major component of a urologist’s practice. For most urologists, part of this process includes the digital rectal examination (DRE). The DRE entails using a finger to enter the rectum and feel a patient’s prostate. The DRE enables physicians to make rough estimates of prostate size and identify abnormalities suggestive of PCa. It is the first physical examination urologists learn because for a long time DREs were the best and only means to screen for and detect PCa. The DRE is ingrained in urology culture, and often is joked about in film and television to the extent that some have called it “the urologist’s handshake.”
In the 1990s came the discovery of the prostate specific antigen (PSA) blood test, which could help physicians identify PCa earlier in its course. Imperfect and somewhat controversial, PSA testing has become the gold standard for PCa screening. But since the adoption of PSA into urologic practice, other major advances in PCa detection have become available, such as the 4K score test or multiparametric magnetic resonance imaging (MRI) of the prostate. These newer tools help urologists decide which patients should move on to a prostate biopsy and which ones can avoid it.
Despite these advancements, most urologists and even general practitioners continue to perform DREs on men seeking PCa screening. Many physicians are adamant that it is still their responsibility to do so. But does the DRE provide helpful information for decision-making or is it an obsolete practice perpetuated by historical dogmatism? We believe it is the latter and it is time to say goodbye to the DRE for PCa screening.
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Limited Value in Decision-Making
When assessing the value of any medical examination, we must study whether it can help guide medical decision-making. For any examination to be useful, it must be accurate. A previous review article found that the DRE detected a mere 28.6% of prostate tumors.1 This means that a negative (normal) DRE does not mean you do not have PCa. In fact, the DRE misses the majority of prostate tumors. So, while a positive (abnormal) DRE may lead physicians to recommend a prostate biopsy, does a negative DRE lead us to recommend against it? The answer is no.
Now some doctors may argue, “What if I feel a nodule? Surely, that means the patient likely has prostate cancer and should get a biopsy.” Well, according to data collected from the Prostate, Lung, Colorectal, and Ovarian (PLCO) screening trial, this is also not the case. Of 5,064 men with an abnormal DRE and normal PSA, only 2% were diagnosed with PCa that would require treatment.2 Therefore, if a negative DRE doesn’t help us feel confident that we can avoid a biopsy, and a positive DRE doesn’t help us feel confident that we need to do a biopsy, then why should physicians perform it at all?
We shouldn’t. Since PSA screening became the norm, physicians have used PSA levels, not the DRE, as the main determining factor in decision-making for PCa screening. The data overwhelmingly supports PSA measurements as a more accurate and objective test for PCa screening. This is reflected in the fact that the American Urological Association (AUA) guidelines for PCa screening only recommend PSA screening and do not recommend the DRE as a primary screening tool. The guidelines state that the DRE, which has no proven benefit as a primary screening test, should only be considered as a secondary test.3
Quick, Cheap, But With Drawbacks
Many physicians would argue that the DRE is a quick, potentially uncomfortable, but largely painless exam that is significantly cheaper to perform than a PSA test. This notion, though seemingly reasonable and innocuous, is incorrect. The DRE is invasive, requiring digital penetration into the rectum. For many men, the prospect of having this performed can be daunting. One study looking at the perception of pain and discomfort of patients during the DRE found that 73% of patients reported moderate or higher discomfort and 61% reported pain.4 The examination may have its drawbacks, but even the mere thought of getting the DRE for many patients may cause other adverse effects that most providers may not be aware of. The stigma associated with the DRE has prevented many men from getting appropriately screened for PCa. A study by Nagler et al demonstrated that only 78% of men would participate in PCa screening that included both PSA and DRE compared with 100% of men who said they would participate in PCa screening that included only a PSA test. According to the study, in a sample of 10,000 men, a PSA test alone would have detected 27 more cancers and avoided 560 negative biopsies.8
Furthermore, studies have shown that following a DRE, PSA, and PSA derivative-based tests such as phi and 4K scores can be skewed because digital manipulation can potentially increase release of prostatic proteins into the bloodstream.5-7 Patients often get their lab work relatively soon after their appointments, so could these false fluctuations in lab values potentially influence decisions for a patient to undergo a prostate biopsy? It’s possible.
“Do no harm” is the foundation of the doctor’s code, and when it comes to the DRE, we are not only causing potential mental and physical harm, but we are potentially setting the stage for inaccurate lab results and an unnecessary barrier to care for many men who fear the exam altogether.
Not Completely Obsolete
We are not saying that the DRE has become completely obsolete. It still has value in certain areas, such as assessing amenability for surgery in patients with known high-risk cancer or those who may require a post radiation prostatectomy. For PCa screening, however, we think it provides limited helpful information and potentially some risks. As the technology in our field continues to evolve, the DRE will continue to become more outdated. More and more literature supports the use of the prostate MRI for screening, and it has become the “go-to test” prior to a biopsy. Compared to the illuminating information we get from an MRI, the DRE is merely a finger in the dark.
As COVID-19 has thrust us forward into the era of telehealth, a change from which we are unlikely to fully return, the DRE no longer even fits into the clinical workflow. Requiring patients to take time off of work to drive to an office where they are potentially put at risk to be exposed to COVID-19 just to be subjected to a DRE makes little sense when a telehealth appointment from home or work to review your lab results is just as effective for PCa screening.
In the end, when evaluating the DRE as a valid tool for PCa screening, we ask both patients and physicians to consider what merits, if any, there really are in performing the examination. If performing a DRE presents a barrier to care, causes pain in two-thirds of the patients who do get screened, and ultimately cannot even provide us with any sound guidance in future decision-making, then we really need to ask ourselves exactly why it is still accepted as a standard of care.
Justin Dubin, MD, is chief urology resident and Sanoj Punnen, MD, MAS, is an associate professor in the department of urology at the University of Miami Miller School of Medicine in Miami, Florida.
References
1. Jones D, Friend C, Dreher A, Allgar V, Macleod U. The diagnostic test accuracy of rectal examination for prostate cancer diagnosis in symptomatic patients: a systematic review. BMC Fam Pract. 2018;19(1):79. doi:10.1186/s12875-018-0765-y
2. Cui T, Kovell RC, Terlecki RP. Is it time to abandon the digital rectal examination? Lessons from the PLCO Cancer Screening Trial and peer-reviewed literature. Curr Med Res Opin. 2016;32(10):1663-1669. doi:10.1080/03007995.2016.1198312
3. Association Urological Association. AUA Clinical Guidelines: Early Detection of Prostate Cancer https://www.auanet.org/guidelines/prostate-cancer-early-detection-guideline2018 [
4. Romero FR, Romero AW, Brenny Filho T, et al. Patients’ perceptions of pain and discomfort during digital rectal exam for prostate cancer screening. Arch Esp Urol. 2008;61(7):850-854. doi:10.4321/s0004-06142008000700018
5. Park SC, Shin YS, Zhang LT, et al. Prospective investigation of change in the prostate-specific antigens after various urologic procedures. Clin Interv Aging. 2015;10:1213-1218. doi:10.2147/CIA.S84570
6. Dutkiewicz S, Stepień K, Witeska A. Effect of digital rectal examination on plasma prostate-specific antigen (PSA). Int Urol Nephrol. 1996;28(2):211-214. doi:10.1007/BF02550863
7. Maccini MA, Westfall NJ, Van Bokhoven A, et al. The effect of digital rectal exam on the 4Kscore for aggressive prostate cancer. Prostate. 2018;78(7):506-511. doi:10.1002/pros.23495
8. Nagler HM, Gerber EW, Homel P, et al. Digital rectal examination is barrier to population-based prostate cancer screening. Urology. 2005;65(6):1137-1140. doi:10.1016/j.urology.2004.12.021
