Surgical margins and biochemical recurrence after the introduction of robot-assisted radical prostatectomy

The DaVinci System is increasingly introduced in many centers worldwide, creating a need for data on surgical outcomes during the early phase of adoption. This study analyzes positive surgical margins (PSMs) and compares outcomes between open, laparoscopic, and robot-assisted radical prostatectomy.

We retrospectively analyzed histopathologic and clinical data from 153, 126, and 721 patients who underwent open, laparoscopic, and robot-assisted radical prostatectomy, respectively. Patients with T2-T3 disease, no lymph node or distant metastases, and no history of neoadjuvant or adjuvant therapy were included. Additionally, surgeon-specific learning curves based on PSM rates were evaluated following the introduction of robot-assisted radical prostatectomy at our institution.

PSM were identified in 254 of 721 (35.2%) robot-assisted procedures, predominantly as focal margins, most often located at the apex. PSM rates were comparable between robot-assisted and laparoscopic surgery and higher after open prostatectomy (p = 0.002). PSM distribution was similar between robot-assisted and open approaches, while apical margins were most frequent following laparoscopic prostatectomy. PSMs were associated with a higher risk of early biochemical recurrence in the entire cohort (p = 0.003). Seminal vesicle invasion was consistently associated with early biochemical recurrence across all surgical approaches. Robot-assisted and laparoscopic surgery were associated with a lower risk of early biochemical recurrence than open prostatectomy. Surgeon-specific analysis demonstrated heterogeneous learning curves, with a reduction in PSM rates after the initial 50-100 cases and stabilization with increasing experience.

Robot-assisted radical prostatectomy achieved PSM rates comparable to laparoscopic and lower than open prostatectomy during the early phase following its introduction. Despite more adverse pathology, robot-assisted surgery was not associated with an increased early biochemical recurrence, supporting its oncologic safety during adoption. These findings reflect the real-world learning curve associated with the implementation of robotic surgery.