442. POSTOPERATIVE ADJUVANT RADIOTHERAPY REDUCES LOCOREGIONAL RECURRENCE IN PATIENTS WITH BORDERLINE RESECTABLE ESOPHAGEAL SQUAMOUS CELL CARCINOMA

Abstract Background borderline resectable esophageal squamous cell carcinoma (Br-ESCC) patients who underwent R0 resection had a significantly improved prognosis. However, local recurrence cannot be ignored. We sought to investigate the efficacy of postoperative adjuvant radiotherapy in reducing locoregional recurrence in patients with Br-ESCC. Methods we established a new resection status, Rbr+, which was defined as no clear boundary between the mass/scar and the outer aortic/tracheal membrane, no visible cancer remaining on the outer aortic/tracheal membrane, and a pathologically negative circumferential margin. patients with Br-ESCC who underwent curative esophagectomy at our center from January 2018 to December 2021 were eligible for this study. Patient characteristics, and perioperative variables were included in this study. univariable and multivariable analyses were performed to compare locoregional recurrence based on the logistic regression model. The Kaplan-Meier method and Cox proportional hazard model were used to compare overall and cause-specific survival. Results A total of 99 patients were included, among whom 27 (27.3%) had a locoregional recurrence. 71.7% (71/99) were classified as Rbr+ resection, and 28.3% (28/99) were classified as Rbr- resection. With a median postoperative follow-up of 55.3 months (range, 24.3-70.8 months), 25 patients out of 71 with Rbr+ resection suffered from local recurrence. However, 2 patients out of 28 with Rbr- resection suffered from locally recurrence. The locoregional recurrence was 25%(7/28) and 41.9%(18/43) in Rbr+ resection with and without postoperative adjuvant radiotherapy. While, the locoregional recurrence was 8.33%(1/12) and 6.25%(1/16) in Rbr- resection patients with and without postoperative adjuvant radiotherapy. Conclusion Rbr+ resection was independently associated with locoregional recurrence in patients with Br-ESCC. postoperative adjuvant radiotherapy was independently associated with overall and cause-specific survival in patients with Br-ESCC.