347. THE EFFICACY OF CONVERSION SURGERY IN ESOPHAGEAL SQUAMOUS CELL CARCINOMA WITH INVASION OF OTHER ORGANS

Abstract Background There are cases of advanced unresectable esophageal squamous cell carcinoma (ESCC) with invasion of other organs that can be successfully treated with chemoradiotherapy and systemic chemotherapy, enabling surgical resection. We actively perform conversion surgery for ESCC with invasion of other organs after definitive chemoradiotherapy or systemic chemotherapy. Methods The patients who underwent conversion therapy in our hospital for ESCC between 2012 and 2022 at participating institutions were retrospectively reviewed. We evaluated patient backgrounds, treatment outcomes, and overall survival (OS) were evaluated. 31 patients were enrolled. 14 conversion cases were performed after chemoradiotherapy, 17 cases were after chemotherapy. All 17 patients received systemic chemotherapy with DCF (Docetaxel + Cisplatin + 5-FU), and all 14 definitive chemoradiotherapy was administered at least 50 Gy. Results There were 24 males and 7 females with a median age of 67 (47-75) years. Involved organs were trachea in 24 cases, aorta in 6 cases, and pulmonary vein in 1 case. 19 patients underwent open esophagectomy, 11 thoracoscopic, and 1 robot-assisted. 14 patients had complications of Clavien-Dindo grade 3, mainly pneumonia, leakage, and recurrent laryngeal nerve palsy. 22 (71%) were performed R0 resection. Recurrence was observed in 20 patients (65%). Overall, 3-year PFS was 22% and 3-year OS was 39%. 3-year OS in patients with R0 resection was 49% while 12.5% in patients with R1 and 2 resection. Conclusion This study showed that conversion therapy could be relatively safely for ESCC patients with organ invasion responded to initial chemotherapy and chemoradiotherapy. Especially in cases R0 resection was performed, good prognosis was obtained.