A Propensity Score-Matched Cohort Study to Evaluate the Association of Lymph Node Retrieval with Long-Term Overall Survival in Patients with Esophageal Cancer

Background Previous studies evaluating the association of lymph node (LN) yield and survival presented conflicting results and many may be influenced by confounding and stage migration. Objective This study aimed to evaluate whether the quality indicator 'retrieval of at least 15 LNs' is associated with better long-term survival and more accurate pathological staging in patients with esophageal cancer treated with neoadjuvant chemoradiotherapy and resection. Methods Data of esophageal cancer patients who underwent neoadjuvant chemoradiotherapy and surgery between 2011 and 2016 were retrieved from the Dutch Upper Gastrointestinal Cancer Audit. Patients with < 15 and >= 15 LNs were compared after propensity score matching based on patient and tumor characteristics. The primary endpoint was 3-year survival. To evaluate the effect of LN yield on the accuracy of pathological staging, pathological N stage was evaluated and 3-year survival was analyzed in a subgroup of patients with node-negative disease. Results In 2260 of 3281 patients (67%) >= 15 LNs were retrieved. In total, 992 patients with >= 15 LNs were matched to 992 patients with < 15 LNs. The 3-year survival did not differ between the two groups (57% vs. 54%;p = 0.28). pN+ was scored in 41% of patients with >= 15 LNs versus 35% of patients with < 15 LNs. For node-negative patients, the 3-year survival was significantly better for patients with >= 15 LNs (69% vs. 61%,p = 0.01). Conclusions n this propensity score-matched cohort, 3-year survival was comparable for patients with >= 15 LNs, although increasing nodal yield was associated with more accurate staging. In node-negative patients, 3-year survival was higher for patients with >= 15 LNs.