Stepwise Improvement of Surgical Quality in Robotic Lateral Pelvic Node Dissection: Lessons from 100 Consecutive Patients with Locally Advanced Rectal Cancer

Hye-Jin Kim, MD, Gyu-Seog Choi, MD, PhD, Jun Seok Park, MD, PhD, Soo Yeun Park, MD, Sung Min Lee, MD. Kyungpook National University Chilgok Hospital

Background: Lateral pelvic lymph node dissection (LPND) is a challenging procedure due to its technical difficulties and higher incidence of surgical morbidity. Owing to its technical difficulties, lateral pelvic lymph nodes (LPNs) may not be dissected completely and thus be remained in the narrow pelvis. Therefore, a steep learning curve is anticipated in doing LPND. However, no study has been conducted about the surgical acquisition of this complex procedure.

Purpose: This study was aimed to evaluate the learning process in performing robotic total mesorectal excision (TME) with LPND for patients with locally advanced rectal cancer.

Material and Methods: This study included 100 patients with rectal cancer who underwent robotic TME with LPND between 2011 and 2017. A cumulative sum analysis and moving average were performed on the basis of the number of unilateral retrieved LPNs for evaluating the learning curve.

Results: The number of retrieved LPNs steadily increased. The cumulative sum model suggested that the learning curve was divided into 4 phases based on 3 cut-off points as follows: learning I (33 patients), learning II (19 patients), consolidation (30 patients), and master (18 patients). At the beginning of the learning phase II, we started standardization of the technique and at the beginning of the consolidation phase, we adopted fluorescence-imaging. The operation time and blood loss were similar during the 4 phases. The unilateral number of retrieved LPNs was significantly greater in the master phase than in the other phases (12.8 vs. 4.9, 8.2, and 10.4, P < 0.001). Urinary problems, including urinary retention and postoperative ?-blocker use, were more frequently observed in the learning phase I than in the master phase (39.4% vs. 16.7%, P = 0.034). During the median follow-up of 44.2 months, local recurrence in the pelvic sidewall occurred in 4 patients in learning phase I and in 1 patient in learning phase II.

Conclusion: The completeness of LPND has increased after adopting the standardized surgical technique and new imaging system, and accumulation of surgeon’s experience. Further study is warranted to determine the oncologic result following each phase.