573. SHORT- AND LONG-TERM RESULTS OF RAMIE IN BORDERLINE CT3 /T4B ESOPHAGEAL CANCER AT INITIAL DIAGNOSIS: COMPARISON WITH CONVENTIONAL MIE

Abstract Background Conversion esophagectomy in patients with locally advanced esophageal cancer, initially deemed unresectable, but which has responded to prior therapy, remains unclear. Recently, the utility of RAMIE for locally advanced esophageal cancer has come under discussion. In this study, we first analyzed the short- and long-term outcomes of RAMIE, then investigated the outcomes of conversion RAMIE in cT3br/T4b patients, and compared them with those of conversion using conventional MIE. Methods Between January 2020 and August 2023, thirty-three patients with locally advanced esophageal cancer initially diagnosed as cT3br/T4b, who underwent RAMIE after prior treatment, were analyzed, and short-term and long-term postoperative outcomes were evaluated. Additionally, these 33 patients who underwent RAMIE for cT3br/T4b were compared to 48 patients with initial cT3br/T4b who underwent conventional MIE during the same period. Results The mean age of RAMIE patients with cT3br/T4b was 63.2 years, with a male-to-female ratio of 26:7, and a clinical stage III/IV distribution of 12/21. Nearly all patients received preoperative treatment with induction chemotherapy (e.g., induction-DCF) or definitive chemoradiation. Among these patients, three underwent R1 or R2 resection. Surgical complications included pneumonia in 18.1% of cases, recurrent nerve palsy in 12.1% (excluding complicated resection cases), and anastomotic leakage in 7.4%. Regarding long-term survival, the 3-year overall survival (3yOS) was 66.2%, and the 3-year disease-free survival (3yDFS) was 48.7% in patients who underwent RAMIE with initial cT3br/T4b. In the 48 patients who underwent esophagectomy with conventional MIE after pretreatment with cT4br/T4b status, the 3yOS was 52.7%, and the 3yDFS was 40.3%. These survival results for conventional MIE were lower than those for patients who underwent RAMIE (p=0.02). Conclusion The short- and long-term outcomes of RAMIE, including cases of T3br/T4 were described, and they were deemed acceptable. Regarding recurrence, local/regional disease control was considered relatively good.