203. SURVIVAL IMPACT OF THORACIC DUCT RESECTION IN PATHOLOGICAL RESPONDERS AFTER TRIPLET CHEMOTHERAPY: EXPLORATORY ANALYSIS FROM MULTICENTER PHASE III TRIAL JCOG1109

Purpose JCOG1109 was a three-arm randomized phase III trial to confirm the survival advantage of docetaxel plus cisplatin plus 5-fluorouracil (DCF) and cisplatin plus 5-fluorouracil (CF) combined with radiotherapy (CF-RT) over CF as preoperative treatment for locally advanced esophageal squamous cell carcinoma. The purpose of this study was to evaluate the survival impact of thoracic duct (TD) resection, and its association with preoperative treatment and pathological response in patients who were enrolled to JCOG1109. Materials and Methods: Patients with potentially resectable advanced thoracic esophageal cancer were randomly assigned to three preoperative therapies and followed by open or thoracoscopic esophagectomy with regional lymphadenectomy. Clinicopathological factors, surgical results which include the status of TD resection, and survival were compared among groups. Furthermore, the survival impact of TD resection was evaluated in the subgroup based on pathological response and preoperative therapy. Results Between December 2012 and July 2018, 601 patients were randomized (CF/DCF/CF-RT; 199/202/200). Of 589 eligible patients to JCOG1109, 541 patients underwent esophagectomy (CF/DCF/CF-RT, 183/181/177). The patients with TD resection showed significantly worse PFS in pathological non-responders, whereas no significant difference in pathological responders. When survival impact of TD resection was evaluated in the subgroup analysis using preoperative treatment and pathological response, patients with TD resection showed significantly better PFS and OS in those who received DCF and achieved pathological response. Conclusion Intensive local control with TD resection in esophagectomy might contribute to improve survival in pathological responders after preoperative DCF therapy.