Correlation of positive prostate sextant biopsy locations to sites of positive surgical margins in radical prostatectomy specimens

Objective: To investigate whether sextant location of positive prostate biopsy predicts the site of positive surgical margins (PSM) at the time of radical prostatectomy (RP) in patients with clinical stage T1c prostate cancer. Methods: A retrospective query of the Center for Prostate Disease Research (CPDR) database at our institution identified 456 patients with clinical stage T1c prostate cancer who underwent standard sextant prostate biopsy prior to RP. Each biopsy was submitted separately for pathologic analysis according to sextant location. The sextant location of positive biopsies was compared to the sites of PSM after RP. Results: PSM were found in 129 of 456 (28%) RP specimens. The incidence of PSM at the prostate apex in patients with a positive or negative apical sextant biopsy was similar (9 and 8% respectively, p>0.05). The incidence of PSM at the prostate base in patients with a positive or negative sextant biopsy of the prostate base was also the same (7% in both groups, p>0.05). As the number of positive biopsy cores on one side of the prostate increased (0, 1, 2, and 3) so did the chance of an ipsilateral PSM (5.4, 16.2, 35.7 and 45.0%, respectively; p<0.005). Conclusions: Positive sextant biopsy location (apex and base) does not correlate with site of PSM at RP. However, ipsilateral PSM are more likely as the number of positive sextant biopsies on that side increases. While pathologic processing of biopsy specimens according to longitudinal prostate location (base, mid and apex) is probably unnecessary, the number of positive biopsies on a given side may be useful preoperative information.