Estimation of clinically significant prostate volumes by digital rectal examination: a comparative prospective study.

Area of Science:

• Urology
• Medical Imaging
• Prostate Health

Background:

• Accurate prostate volume quantification is crucial for selecting benign prostatic hyperplasia (BPH) patients for medical therapy (e.g., 5-alpha-reductase inhibitors [5-ARIs]) and surgical interventions.
• Digital rectal examination (DRE) is a common clinical assessment, but its reliability in estimating prostate volume needs validation for BPH management.

Purpose of the Study:

• To evaluate the reliability of digital rectal examination (DRE) in estimating prostate volume.
• To determine if DRE can accurately identify patients suitable for 5-alpha-reductase inhibitor (5-ARI) therapy based on prostate size.

Main Methods:

• A prospective study involving 248 patients requiring transrectal ultrasound (TRUS) guided prostate biopsy.
• Each patient underwent two DREs by clinicians who categorized volume (small, medium, large) and estimated size; TRUS provided the reference volume measurement.

Main Results:

• No significant difference was observed between the two DRE prostate volume estimations (p = 0.8).
• DRE underestimated prostate volumes in 59% (small), 58% (medium), and 53% (large) of cases.
• However, DRE accurately estimated clinically relevant volumes greater than 30 cc in 94.5% of patients.

Conclusions:

• Digital rectal examination demonstrates a 94% positive predictive value for identifying prostates larger than 30 cc.
• DRE can be sufficient for selecting patients for 5-ARI therapy, particularly when a prostate volume >30 cc is suspected.
• Transrectal ultrasound (TRUS) may be necessary for precise volume assessment in cases between 25-30 cc and above 80 cc.