The Relationship between Lymph Node Ratio and Survival Benefit with Adjuvant Chemotherapy in Node-positive Esophageal Adenocarcinoma

BACKGROUND: We hypothesized that the ratio of positive lymph nodes to total assessed lymph nodes (LNR) is an indicator of cancer burden in esophageal adenocarcinoma and may identify patients who may most benefit from adjuvant chemotherapy (AC). OBJECTIVE: The aim of this study was to discern whether there is a threshold LNR above which AC is associated with a survival benefit in this population. METHODS: The 2004-2015 National Cancer Database was queried for patients who underwent upfront, complete resection of pT1-4N1-3M0 esophageal adenocarcinoma. The primary outcome, overall survival, was examined using multivariable Cox proportional hazards models employing an interaction term between LNR and AC. RESULTS: A total of 1733 patients were included: 811 (47%) did not receive AC while 922 (53%) did. The median LNR was 20% (IQR 9-40). In a multivariable Cox model, the interaction term between LNR and receipt of AC was significant (p=0.01). A plot of the interaction demonstrated that AC was associated with improved survival beyond a LNR of about 10-12%. In a sensitivity analysis, the receipt of AC was not associated with improved survival in patients with LNR