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341. SEX-RELATED DIFFERENCES IN TREATMENT STRATEGY AND OUTCOMES AFTER ESOPHAGECTOMY FOR CANCER


 Esophageal cancer predominantly occurs in men, accounting for 75–89% of patients. Chosen treatment modalities and their related toxicities among male and female esophago-gastric cancer patients show significant variabilities, but there are only scarce data on the outcomes. This multicenter study aimed to assess potential sex-related differences in treatment allocation and outcomes, i.e. long-term survival in a large cohort of esophageal cancer patients.
 All consecutive patients who underwent oncological esophagectomy from 2009 to 2015 in the 20 ENSURE study group centers (NCT03461341) were included bar patients with missing data on gender, histologic type and treatment protocol. We used univariable and multivariable logistic regression for gender-related differences in treatment allocation and types, such as surgical approach, neoadjuvant treatment regimen, and use of cancer-specific treatment in case of tumor recurrence. Time-to-event outcomes, such as overall survival (OS), disease free survival (DFS), and disease-specific survival (DSS) were assessed with univariate and multivariate Cox regression. Results are shown as hazard ratios (HR) and 95% confidence intervals (CI).
 Overall, 3974 patients were analyzed, 3083 males (77.6%) and 891 females (22.4%). The median age was similar, whereas the histological type was adenocarcinoma in 77.5% of male and 52.2% of female patients. Gender was not predictive for neoadjuvant treatment or systemic cancer-specific therapy in case of tumor recurrence. Minimally invasive surgery was performed more frequently in male patients compared to females (OR 1.29, 95%CI 1.00–1.66). In multivariate analysis, even after adjustment for age, histology, postoperative complications and treatment protocol, male patients had poorer OS (HR 1.29 95%CI 1.12–1.48), DFS (HR 1.26, 95%CI 1.09–1.46) and DSS (HR 1.34, 95%CI 1.15–1.56).
 Patient sex was not associated with the use of systemic cancer-related treatment, although minimally invasive surgery was more frequently performed in male patients. Females had more favorable long-term overall and cancer-specific survival, even when age, histology, treatment modalities, and complications were accounted for. This sex-related prognostic difference has been previously suggested, especially for squamous cell cancer, although the precise mechanism by which gender influences esophageal cancer outcomes remains poorly understood and warrants further assessment.