645. CLINICAL SIGNIFICANCE OF LOCAL TREATMENT FOR RECURRENCE WITHIN THE SURGICAL FIELD AFTER RADICAL ESOPHAGECTOMY

Abstract Background In recent years, more aggressive multidisciplinary treatment and minimally invasive approaches with meticulous lymph node dissection have become the standard in esophageal cancer surgery, but recurrence cases within the surgical field after radical resection are unfortunately frequently observed. We will compare the clinicopathological characteristics of the cases of intra-sugical field recurrence with those of extra-surgical and both intra- and extra-surgical field recurrence and discuss their significance in light of the results of local treatment for intra-surgical field recurrence. Subjects The study included 130 cases of intra-surgical field recurrence among 490 esophageal cancer patients who underwent radical subtotal esophagectomy and cervical anastomosis (Mckeown-esophagectomy) with right thoracic approach between January 2013 and April 2019. Results The 130 cases of recurrence were categorized as intra-surgical field recurrence (Group I)/extra-surgical field (Group O)/intra- and extra-surgical field (Group I+O): 19/86/25. Preoperative factors: Tumor localization tended to be more common in Ut in group I (p=0.078), but there were no other differences such as cStage or preoperative treatment. Intraoperative/postoperative factors: I+O group had significantly more blood loss (p=0.045), but there were no other differences in the range of lymph node dissected field, number of dissected lymph nodes, combined resection of the thoracic duct, postoperative complications, hospital stay, or histological therapeutic effect. 19 patients in group I had 17 patients (89.5%) who received initial local treatment (surgery/CRT/RT: 4/7/6). The response rate (R0 resection or CR+PR) was 58.8%. Compared to cervical and upper mediastinal lymph node recurrence, the response rate to initial local treatment tended to be lower in patients with middle and lower mediastinal lymph node and anastomotic recurrence (80%/43%, p=0.145). Discussion Intra-surgical field recurrence after radical resection tended to be more common in the primary site of Ut. Recurrence in the upper mediastinal lymph nodes in the cervical region shows a relatively high response rate to local treatment, and long-term recurrence-free ("cure") is achieved. On the other hand, mid and lower mediastinal lymph node and anastomotic recurrences have a low response rate to local treatment and should be complemented with more systemic treatment, such as sequential ICI to initial treatment.