Clinical outcomes of robot-assisted intersphincteric resection for low rectal cancer: comparison with conventional laparoscopy and multifactorial analysis of the learning curve for robotic surgery.

BACKGROUND: This study evaluated the feasibility of robot-assisted intersphincteric resection (ISR) for low rectal cancer. Further, we attempted to analyze the learning curve for robotic surgery.
METHODS: A total of 64 patients were retrospectively chart-reviewed. Patients were classified into a laparoscopic procedure (n = 28) group and a robot-assisted (n = 36) group. Comparisons of age, gender, clinical staging, operating time, complications, and pathologic status were analyzed. Besides, we used a seventh-order moving average method for the construction of a learning curve in robotic surgery.
RESULTS: Operating time was 374.3 min (range, 210-570 min) in the laparoscopic group and 485.8 min (range, 315-720 min) in the robotic group, with statistical difference between these two groups (P < 0.001). Thirteen patients (46.4 %) received diverting stoma in the laparoscopic group and seven patients (19.4 %) in the robotic group, with statistical difference between these two groups (P = 0.021). Operative experience of robotic ISR showed that the mean operating time was 519.5 min (range, 360-720 min) in the first stage and 448.2 min (range, 315-585 min) in the second stage, with statistical difference between these two stages (P = 0.02). Multifactorial analysis showed that protective diverting stoma creation or neorectum necrosis was not associated with age, sex, pretreatment T stage, or surgeons' experience.
CONCLUSIONS: Our data shows that robot-assisted ISR for low rectal cancer is feasible and safe with no compromising oncological outcomes. The surgeons' experience improves operating time in robotic surgery.