Does intraoperative frozen section really predict significant positive surgical margins after robot-assisted laparoscopic prostatectomy? A retrospective study

We investigated the relationship between positive surgical margin (PSM)-related factors and biochemical recurrence (BCR) and the ability of intraoperative frozen sections to predict significant PSM in patients with prostate cancer. The study included 271 patients who underwent robot-assisted laparoscopic prostatectomy with bilateral nerve sparing and maximal urethral preservation. Intraoperative frozen sections of the periurethra, dorsal vein, and bladder neck were analyzed. The ability of PSM-related factors to predict BCR and significant PSM was assessed by logistic regression. Of 271 patients, 108 (39.9%) had PSM and 163 (60.1%) had negative margins. Pathologic Gleason score ≥8 (18.9% vs 7.5%, P = 0.015) and T stage ≥T3a (51.9% vs 24.6%, P < 0.001) were significantly more frequent in the PSM group. Multivariate analysis showed that Gleason pattern ≥4 (vs <4; hazard ratio: 4.386; P = 0.0004) was the only significant predictor of BCR in the PSM cohort. Periurethral frozen sections had a sensitivity of 83.3% and a specificity of 84.2% in detecting PSM with Gleason pattern ≥4. Multivariate analysis showed that membranous urethra length (odds ratio [OR]: 0.79, P = 0.0376) and extracapsular extension of the apex (OR: 4.58, P = 0.0226) on magnetic resonance imaging (MRI) and positive periurethral tissue (OR: 17.85, P < 0.0001) were associated with PSM of the apex. PSM with Gleason pattern ≥4 is significantly predictive of BCR. Intraoperative frozen sections of periurethral tissue can independently predict PSM, whereas sections of the bladder neck and dorsal vein could not. Pathologic examination of these samples may help predict significant PSM in patients undergoing robot-assisted laparoscopic prostatectomy with preservation of functional outcomes.