Computer-assisted comparative analysis of four sector and six-sector biopsies of the prostate

Objectives. To assess the potential difference in positive biopsy rates between four-sector and six-sector biopsy methods. Methods. This computer-assisted analysis is based on the records of 156 consecutive patients previously diagnosed with Tie cancer on systematic sextant biopsy of the peripheral zone. For each patient the computer randomly deleted one biopsy result from the left and right prostatic lobes. The deletion process was repeated 1000 times. Based on four randomly chosen biopsy cores, we determined the number of undetected cancers initially diagnosed with sextant biopsy. Results, Based on four-sector biopsy cores of the peripheral zone, between 6 and 30 (3.8% to 19.2% of cases) nonpalpable, isoechoic prostate cancers that were detected with sextant biopsy would have remained undiagnosed. Conclusions. Our results suggest that the number of biopsy cores used in the early detection of nonpalpable, isoechoic prostate cancer may substantially affect the rate of positive findings. Copyright 1996 by Elsevier Science Inc.