What happens during a digital rectal examination (DRE)?

What to Expect During a Digital Rectal Examination (DRE)

A digital rectal examination involves a physician inserting a gloved, lubricated finger into the rectum to palpate the prostate gland through the anterior rectal wall, assessing for size, symmetry, consistency, nodules, induration, or asymmetry that may indicate prostate cancer or other abnormalities. 1, 2

Pre-Examination Preparation

• You should empty your bladder before the examination if urinary retention is being evaluated 3
• The examination requires adequate lighting and proper positioning 3

What the Physician Will Do: Step-by-Step

Initial Inspection Phase

• The physician will first separate the buttocks and visually inspect the perianal area for fecal soiling, skin problems, hemorrhoids, fissures, or fistulas 3
• You may be asked to bear down as if having a bowel movement so the physician can observe for excessive perineal descent (>3 cm suggests pelvic floor dysfunction) or mucosal prolapse 3
• The physician will test the anal reflex by lightly scratching or pricking the perianal skin—absence of this reflex may indicate neurologic problems 3

Digital Palpation

• The physician will insert a gloved, lubricated finger into the rectum to assess multiple structures 1, 3
• Immediately upon insertion, resting anal sphincter tone is assessed (normal, increased, or decreased) 3
• You will be asked to squeeze to evaluate the strength and duration of sphincter contraction 3
• The physician will palpate the puborectalis muscle posteriorly—acute tenderness here suggests levator ani syndrome 3

Systematic Rectal Wall Examination

• The examining finger will sweep circumferentially through all quadrants of the rectal wall, reaching approximately 8-10 cm into the rectum 3
• The physician palpates for masses, polyps, strictures, or areas of induration 3

Prostate Examination (in Men)

• The prostate is palpated anteriorly through the anterior rectal wall, with the physician assessing size, symmetry of both lobes, consistency, and presence of nodules or induration 1, 3
• The region of the prostate adjacent to the rectal wall is where tumors commonly develop; hard regions or asymmetry may indicate prostate cancer 1
• However, it's important to understand that in most cases (96.8% according to one study), the physician cannot palpate the entire prostate—only the apex and lower portions are typically reachable 4

Functional Assessment

• You will be instructed to push out the examining finger as if having a bowel movement to assess coordination of defecatory effort 3
• This evaluates your ability to relax pelvic floor muscles during simulated defecation 3

What Constitutes Normal Findings

• Normal sphincter tone at rest and with squeeze 5
• No tenderness, masses, or abnormalities 5
• Intact anal reflex and appropriate perineal sensation 5
• Normal perineal descent (1-3 cm) during simulated evacuation 5
• No prolapse or patulous opening 5

Important Caveats About DRE Limitations

Technical Limitations

• DRE tends to underestimate prostate size—if the prostate feels large on DRE, it is usually significantly enlarged on ultrasound 2, 3
• The anatomical location and volume of the prostate, as well as the examiner's finger length, limit what can be palpated 4
• Only the apex and lower portions of the prostate are typically reachable in most men 4

Examiner Variability

• Interexaminer agreement among urologists for detecting prostate cancer is only fair (kappa = 0.22), with even greater variability between faculty and resident examiners 6
• This means different physicians may interpret findings differently 6

Clinical Context

• DRE should not be used as a stand-alone screening test for prostate cancer but must be combined with PSA measurement 2, 3
• DRE is performed by clinicians skilled in detecting subtle abnormalities of the prostate and rectum 2, 3
• Despite its limitations, DRE can detect clinically significant prostate cancers at PSA levels below 4 ng/mL—20% of cancers detected by DRE alone had Gleason scores ≥7 or were non-organ-confined 7
• If DRE alone were used for screening, 40% of cancers would be missed; if PSA alone were used, only 10% would be missed, but combining both methods provides the most complete evaluation 8

Post-Examination Documentation

The physician will systematically document findings including sphincter tone, masses, tenderness, prostate characteristics, stool characteristics, and any abnormalities detected 3