O30 NON-RADICAL ESOPHAGECTOMY FOR ESOPHAGEAL CANCER; A NATIONWIDE STUDY ON INCIDENCE, RISK FACTORS AND OUTCOMES IN SWEDEN

Abstract Aim To identify potential risk factors for a microscopically non-radical esophageal cancer resection (R1) and investigate how such a resection affects long-term survival. Background & Methods Esophageal cancer resections that are considered R1 have been associated with worse survival. The Swedish National Register for Esophageal and Gastric Cancer includes information on all esophageal cancer resections in Sweden. All patients having undergone esophageal resection with curative intent 2006-2017 were included. Risk factors for R1 resection were assessed through logistic regression. Factors predicting five-year survival were assessed through Cox-regression, adjusted for T-stage, N-stage, age and R-status. Results The study included 1,504 patients. The margins were microscopically involved in 146 patients (10%). Of these the circumferential margin was involved in 115 (8%). The proximal margin was involved in 55 patients (4%) and the distal in 30 (2%). In 54 (4%) specimens two margins were involved. Independent risk factors for R1-resection were absence of neoadjuvant treatment and clinical T3 stage or higher. The 5-year survival for the entire cohort was 41%, but only 19% for those with an R1 resection. Independent risk factors for death within 5-year from resection were regional lymph node metastasis (Hazard Ratio (HR) 2.6 (95% CI 2.2-3.1), histopathological stage T3 or higher (HR 1.2 95% CI 1.1-1.5), age above 60 years and R1-resection (HR 1.6 95% CI 1.4-2.0) Conclusion Involved margin in the resected specimen is an independent risk factor predicting worse 5-year survival. Besides striving for adequate surgical margins, the rate of R1-resections could be decreased through neoadjuvant treatment in fit patients.