Digital Rectal Examination (DRE) | Prostate Rectal Exams | Prostate Cancer

DRE - How to perform a Digital Rectal Exam

Part 2

The DRE remains a cornerstone in the diagnosis of prostate cancer, owing to its ease, lack of cost, low risk, and contribution to detection of cancer in men with normal PSA levels. With its low position in the pelvis, below the bladder neck, the anatomic position of the prostate allows palpation of the posterior wall by the finger placed per rectum. The DRE is used to diagnose benign prostatic hyperplasia (BPH) and macroscopic prostate cancer and to evaluate its extent.

However, DRE is only moderately sensitive in diagnosing small, early-stage prostate cancer, and it is not sensitive in detecting disease minimally extended beyond the capsule. The DRE is useful toward prostate cancer detection, because most cancers arise in the peripheral zone of the prostate. The test is obviously limited in that some tumors are microscopic, and others arise in the transitional zone within the inner aspects of the prostate and are less amenable to digital detection.

DRE has been used for centuries under the Latin term "palpatio per anum". The use of the DRE in the diagnosis and staging of prostate cancer was accurately described by Marion in 1921:

"Prostate cancer is generally easy to differentiate from BPH. The consistency of the prostatic mass is distinctive and, rather than elastic, hard and almost always irregular. The form instead of being regular rounded is frequently uneven. Finally, instead of feeling a distinctive border, one feels a continuation with the surrounding tissue, many times on the superior and external borders. Sometimes the mass is regular and limited but hard as wood. This is cancer. Sometimes one feels no mass but a simple hard nodule without precise delineation in the tissue."

"The diagnosis becomes delicate when one deals with an early cancer and is only characteristic by the feeling of a few hard nodules in a mass that has all the specifications of BPH. They may be BPH but are very suspicious, especially if they do not disappear by rectal massage. The diagnosis in the early stage of the disease is very delicate and even experienced urologists are sometimes obliged to reserve their diagnosis for a certain time."

[Marion G, ed. Traite d' urologie II. Paris: Masson, 1921:1050.]

Although nodularity is obviously a significant finding on DRE, the classic study by Jewett (8) showed that only 50% of the lesions palpated by this clinical expert and considered suspicious were actually cancer on biopsy.