Impact of Variations in Prostatic Apex Shape on Apical Margin Positive Rate After Radical Prostatectomy: Robot-Assisted Laparoscopic Radical Prostatectomy vs Open Radical Prostatectomy.

Abstract

To evaluate the effects of prostatic apex shape variations on positive apical margin (PAM) rate after radical prostatectomy (RP) by undertaking a comparative study of robot-assisted laparoscopic radical prostatectomy (RALP) vs open radical prostatectomy (ORP). A total of 3324 cases of RP (1004 ORP and 2320 RALP) from January 2004 to March 2017 were retrospectively reviewed. All patients underwent preoperative MRI and the cohorts were stratified into four categories according to prostatic apical shape at the midsagittal plane. Between ORP and RALP groups, age, body mass index, preoperative prostate-specific antigen (PSA), biopsy and pathological Gleason score (GS), clinical and pathological stage, and prostatic apex shapes were compared. Logistic regression analyses were performed to evaluate significant predictors of PAM. Propensity adjustments were undertaken before statistical analysis to minimize the lack of randomization. ORP and RALP groups showed no significant differences in age, body mass index, PSA, biopsy and pathological GS, clinical and pathological stage, as well as prostatic apical shape variations. The ORP group showed a PAM of 17.5% that was significantly higher than 12.3% of the RALP group (p < 0.001). Both groups showed the highest PAM with apical type 3, which is the apex covering the posterior aspect of membranous urethra (ORP 33.9%, RALP 28.5%). In unadjusted data, multiple logistic regression analysis showed that prostate apical type 3 was a significant independent predictor of PAM, but other apex types were not. Prostate apical type 3 was a significant independent predictor of PAM. The RALP group showed better outcomes in terms of PAM compared with the ORP group. Preoperative MRI might be a potentially useful tool for preoperative designing of the surgical modalities.