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.