Favorable risk factors in patients with positive surgical margin after robot-assisted radical prostatectomy

Introduction: Positive surgical margin (PSM) has classically been associated with biochemical recurrence (BCR) following radical prostatectomy (RP) and immediate adjuvant radiotherapy has been advocated based on two large randomized prospective clinical studies. However, a significant percentage of patients with PSM never experience BCR. This study evaluated factors potentially affecting risk of BCR among the patients with PSM after robot-assisted radical prostatectomy (RARP). Materials and methods: From a prospectively maintained database, 699 patients with localized prostate cancer who underwent a RARP without any adjuvant therapy were identified. Median follow up was 46.0 months. To determine the pathologic and clinical factors that influenced BCR, univariate and multivariate analyses using the Cox proportional hazards model were performed. BCR-free survival curves were estimated with Kaplan-Meier method. Results: Surgical margins were positive in 115 patients (16.5%), of whom 23 (20%) had BCR. In the univariate analyses, serum PSA level, surgical Gleason score (GS), and non-organ confined disease were significantly associated with BCR in men with PSM. Multivariate Cox analysis showed that BCR was significantly associated with PSA (p = 0.011), and the surgical GS (p = 0.008). In patients with lower PSA cutoff (5.3 ng/mL), GS <= 7, and organ-confined disease, there were no BCR. Conclusions: In this study, we identified favorable risk factors inpatients with PSM following RARP. The results suggest that immediate adjuvant therapy for PSM may not be necessary in men with Gleason score 7 or less, organ-confined disease, and low preoperative PSA.