Impact of diverse shapes of prostatic apex on positive apical margin rate and biochemical recurrence following laparoscopic radical prostatectomy

Abstract

Objective: To explore the effects of various forms of prostatic apex on positive apical margin rate (PAM) and biochemical recurrence (BCR) after laparoscopic radical prostatectomy. Methods: A retrospective analysis of 309 patients (aging (65±6) years) who were experienced laparoscopic radical prostatectomy from January 2010 to December 2016 at the Department of Urology, First Affiliated Hospital of Fujian Medical University. According to the relationship between prostate apex and membrane urethra at the mid-sagittal plane of preoperative MRI, all patients were classified into 4 categories. There were 31 patients for type 1, apex covering both anterior and posterior aspects of membranous urethra, 139 patients for type 2, apex covering anterior side of membranous urethra, 63 patients for type 3, apex covering posterior aspect of membranous urethra, 76 patients for type 4, apex not covering membranous urethra. PAM and BCR after operation were compared between this four groups respectively. The χ(2) test was used to compare PAM among the 4 types. Logistic regression analysis were undertaken to analyze the factors affecting PAM. Cox's proportional hazards regression model was undertaken to identify the variables influencing BCR. Results: There was no significant difference in the 4 groups concerning age, body mass index, prostate volume, preoperative prostate-specific antigen (PSA) value, postoperative Gleason score and pathological stage (P>0.05).The median follow-up time was 32 months (ranged from 12 to 60 months).The data showed that the apical type 3 patients has the highest PAM. There was statistical difference among the 4 groups in PAM (χ(2)=15.592, P=0.001). Preoperative level of PSA (OR=20.356, 95% CI: 2.440 to 169.810, P=0.005), postoperative Gleason score (OR=4.113, 95% CI: 1.911 to 8.849, P=0.001), pathological stage (OR=3.422, 95% CI: 1.600 to 7.319, P=0.002) and apical type 3 (OR=6.134, 95% CI: 2.196 to 17.132, P=0.001) were independent relactive factors of PAM. Preoperative level of PSA (HR=1.362, 95% CI: 1.006 to 1.843, P=0.045), postoperative Gleason score (HR=1.920, 95% CI: 1.384 to 2.665, P=0.001), pathological stage (HR=1.476, 95% CI: 1.098 to 1.983, P=0.010), PAM (HR=3.497, 95% CI: 2.407 to 5.081, P=0.001)and apical type 3 (HR=1.828, 95% CI: 1.266 to 2.639, P=0.001) were independent prognosis factors of BCR. Conclusion: Prostate apical type 3 could be a significant independent predictor of PAM, and an independent prognosis factor for BCR.