453. TREATMENT AND SURVIVAL OF PATIENTS WITH A POSITIVE RESECTION MARGIN AFTER NEOADJUVANT CHEMORADIOTHERAPY AND ESOPHAGECTOMY

Abstract

Abstract Background Esophagectomy after neoadjuvant chemoradiotherapy (nCRT) is associated with a tumor-positive resection margin in 4–9% of patients. Although survival in patients with a positive margin is decreased, Western guidelines do not recommend adjuvant systemic/local treatment after esophagectomy. The aim of this study was to assess whether patients underwent adjuvant therapy, regardless the lack of evidence from guidelines, and to evaluate the overall survival (OS) in patients that underwent esophagectomy and had a positive resection margin. Methods All patients diagnosed with resectable (cT2-4a/cTxN0–3/NxM0) esophageal or junctional cancer that underwent nCRT followed by esophagectomy between 2015 and 2021 were selected from the Netherlands’ Cancer Registry. Included were patients with a tumor-positive resection margin. The primary endpoint was the proportion of patients that started adjuvant treatment ≤16 weeks after esophagectomy, including chemotherapy, radiotherapy, immunotherapy or targeted therapy. Secondary outcome OS was calculated from date of surgery until date of death or last day of follow-up, using the Kaplan Meier method. Results Among the 300 included patients, 98.7% had a microscopically irradical resection (R1), while 1.3% had a macroscopically irradical resection (R2). The median age was 67 (interquartile range 60–72) years and WHO 0–1 (89.3%). Esophagectomy was performed open (8.3%), laparoscopically (57.7%) or robot-assisted (33%) and via transthoracic (89.7%) or transhiatal approach (8.7%). Some 71% of tumors had a partial response (Mandard category 1–3) or no pathological response (Mandard 4–5; 12.7%) to nCRT. One patient underwent external radiotherapy after esophagectomy. Twenty patients (7%) underwent adjuvant immunotherapy (nivolumab), despite their irradical resection. Median OS of all patients was 18.6 months (95% CI 14.7–22.4). Conclusion Real-world population level data showed that 7% of patients were treated with adjuvant immunotherapy, despite lack of evidence of the benefit thereof in patients with an irradical resection. This underlines the need for better neoadjuvant therapy leading to less irradical resections, as well as prospective studies evaluating adjuvant therapy in patients with an irradical resection.