Robot-assisted esophagectomy with extended mediastinal lymph node dissection: The learning curve and surgical outcomes.

457 Background: We have performed thoracoscopic surgery (TMIE) and robot-assisted surgery (RAMIE) for esophageal cancer with extensive mediastinal lymph node dissection, including resection of the sympathetic nerve layers and the thoracic duct. We studied the learning curve, short-term results, and mid-to-long-term outcomes of RAMIE for esophageal cancer at our institution. Methods: We compared surgical times at different stages of the procedure. For mid to long-term outcomes, we analyzed 360 cases of TMIE/RAMIE performed between January 2009 and June 2022, comparing the incidence of postoperative complications, recurrence-free survival, and patterns of recurrence between RAMIE and TMIE. Recurrent laryngeal nerve palsy (C-D I) was evaluated using postoperative endoscopy or contrast swallowing tests to assess even mild paralysis. Results: The average console time in the thoracic procedure was 234.4 minutes, with Group A (294.5 minutes, range: 211-397 minutes) showing significantly longer times compared to Group B (190.5 minutes, range: 130-257 minutes). Blood loss was almost 0ml in 10 cases (50%) in Group A and 25 cases (62.5%) in Group B. Postoperative complications included pneumonia in 5 cases (8.3%) and recurrent laryngeal nerve palsy (C-D III) in 5 cases (8.3%), with no significant difference between the groups. However, surgical time for lymph node dissection around the recurrent laryngeal nerve was significantly shorter in Group B compared to Group A. Long-term analysis included 326 TMIE and 34 RAMIE cases. Mild recurrent laryngeal nerve palsy (>C-D I) was observed in 92 cases (28%) of TMIE and 7 cases (21%) of RAMIE, showing a lower tendency in the RAMIE group (p=0.338). Pneumonia (>C-D II) occurred in 57 cases (18%) in the TMIE group and 3 cases (9%) in the RAMIE group, with a relatively lower incidence in the RAMIE group (p=0.178). For patients with cT1N0M0 who did not receive preoperative chemotherapy, the 3-year recurrence-free survival rates were 95% for TMIE and 93% for RAMIE. Conclusions: RAMIE demonstrated a significant reduction in operative time due to the standardization of the procedure, particularly in the dissection of recurrent laryngeal nerve lymph nodes and other upper mediastinal maneuvers. RAMIE also showed a potential reduction in the incidence of recurrent laryngeal nerve palsy and pneumonia compared to TMIE. In terms of long-term outcomes, RAMIE maintained local control similar to TMIE, with further improvements in safety expected.