Bad medicine: digital rectal examinationBMJ 2011; 342 doi: http://dx.doi.org/10.1136/bmj.d3421 (Published 01 June 2011) Cite this as: BMJ 2011;342:d3421
- Des Spence, general practitioner, Glasgow
Rectal examination was a “must do” examination during my medical education, but in the real world of clinical practice I have always wondered why. For many years I taught medical students rectal examination using plastic dummies. I explained that largely it was a useless examination, but this met with hostility: “They wouldn’t teach us this if it was pointless, Dr Spence!” It was futile to challenge the orthodoxy, so I approached the clinical exams like a drama teacher might approach an end of term school musical. The clinical examiners always said it was “great,” but we all knew it was amateurish nonsense. All clinical examinations are in fact clinical “tests,” like radiograph scans and blood analysis. They should be subject to the reflective rigour of the positive predictive values, error rates, and the rest. So does rectal examination have purpose?
Inspection has value, to examine for warts, fissures, dermatitis, and piles. But what of the role of digital rectal examination? Logically it has perhaps two purposes: to detect rectal tumours and to palpate the prostate. It has no obvious logical diagnostic value in appendicitis or acute abdominal pain, which were once traditional indications.
Consider the rationale for detecting rectal tumours. The patient presents to the doctor with rectal symptoms. If the patient is young then the possibility of malignant disease is extremely low, so digital rectal examination as screening test has no value. But if symptoms are persistent or in older patients with bleeding, change in bowel habit, or tenesmus this would warrant urgent definitive endoscopsy. So how would a digital rectal examination change management? A negative result might offer false reassurance and positive result might be false, generating unnecessary anxiety. Either way this would not change the need for urgent inspection of the bowel.
What about examining the prostate? The “annual” is common practice in the United States but has not been shown to reduce mortality (Cochrane Data Syst Rev 2006;3:CD004720, doi:10.1002/14651858.CD004720.pub2, and BMJ 2011;342:d1539, doi:10.1136/bmj.d1539), and it is associated with a possible rate of overdiagnosis of prostate cancer of 50% (Br J Cancer 2006;95:401-5, doi:10.1038/sj.bjc.6603246), resulting in unnecessary treatment, destructive surgery, and psychological sequalea. Even patients who present with “prostatic symptoms” (now more correctly referred to as “lower urinary tract symptoms”) are at no greater risk of prostate cancer than those without symptoms (BJU Int 2000;85:1037-48). With prostatitis the underlying cause is debated, and the role of rectal examination is only part of the assessment. Rectal examination of the prostate may cause more harm than good.
Rectal examination is unpleasant, invasive, and as an investigation has unknown sensitivity and specificity. In a young population digital rectal examination has almost no value, and in older patients may have very occasional and limited indication. It is time to question the once standard practice of routine digital rectal examination because it represents flimsy thinking and bad medicine.
Cite this as: BMJ 2011;342:d3421