Reality of nerve sparing and surgical margins in surgeons' early experience with robot-assisted radical prostatectomy in Japan.

Objective: To analyze nerve sparing performance at an early stage of robot-assisted radical prostatectomy, and the correlation between the surgeons' experience and the risk of a positive surgical margin in patients treated with robot-assisted radical prostatectomy.

Methods: Patients' records from January 2009 to March 2013 were retrospectively reviewed, and 3469 patients with localized prostate cancer were identified at 45 institutions. Individual surgeon's experience with nerve sparing was recorded as the number of nerve sparing cases among total robot-assisted radical prostatectomies beginning with the first case during which nerve sparing was carried out. Patients were selected by propensity score matching for nerve sparing, and predictive factors of positive surgical margins were analyzed in patients with and without positive surgical margins.

Results: A total of 152 surgeons were studied, and the median number of robot-assisted radical prostatectomy cases for all surgeons was 21 (range 1-511). In all, 54 surgeons (35.5%) undertook nerve sparing during their first robot-assisted radical prostatectomy case. For 2388 patients selected with (1194) and without (1194) nerve sparing, predictive factors for positive surgical margin were high initial prostate-specific antigen level (P < 0.0001), high biopsy Gleason score (P = 0.0379), presence of neoadjuvant hormone therapy (P = 0.0002) and surgeon's experience with >100 cases (P = 0.0058). Thus, nerve sparing was not associated with positive surgical margins.

Conclusion: The surgeon's experience influences the occurrence of positive surgical margins, although a considerable number of surgeons carried out nerve sparing during their early robot-assisted radical prostatectomy cases. Surgeons should consider their own experience and prostate cancer characteristics before carrying out a nerve sparing robot-assisted radical prostatectomy.