The optimal systematic prostate biopsy scheme should include 8 rather than 6 biopsies: results of a prospective clinical trial.

PURPOSE

We define the optimal systematic biopsy regimen to detect carcinoma of the prostate.

MATERIALS AND METHODS

A total of 483 consecutive patients referred for an abnormal digital rectal examination and/or prostate specific antigen (PSA) 4.0 ng./ml. or greater underwent transrectal ultrasound and systematic biopsy. Lateral biopsies of the peripheral zone at the base and mid gland were added to the routine sextant biopsy regimen for a total of 10 systematic biopsies of the peripheral zone. Patients with a prostate greater than 50 cc also underwent systematic sextant transition zone biopsy in the mid lobar parasagittal plane. Detection rates of the various regions were assessed. Various biopsy schemes were then created and cancer detection rates were compared using McNemar's test.

RESULTS

Of the patients 42% (202 of 483) had cancer on biopsy. Traditional sextant biopsies missed 20%, while a sextant regimen incorporating lateral peripheral zone biopsies of the mid gland and base along with the apex missed 11% of the cancers. The combination of sextant and lateral peripheral zone biopsies (10-biopsy scheme) detected 194 cancers (96%). The 8 missed cancers were detected by lesion directed (5) or transition zone (3) biopsies. Eliminating the mid lobar base biopsies from the systematic 10-biopsy peripheral zone regimen resulting in an 8-biopsy peripheral zone regimen decreased detection from 96% to 95%.

CONCLUSIONS

The 6 systematic biopsies of the peripheral zone are inadequate and a minimum of 8, including the apex, mid lobar mid gland, lateral mid gland and lateral base, should routinely be performed.