A large real-world cohort study of examined lymph node standards for adequate nodal staging in early non-small cell lung cancer

BACKGROUND: The current National Comprehensive Cancer Network (NCCN) guidelines for non-small cell lung cancer (NSCLC) recommend that surgeons sample is not clear. We aimed to define a minimal number of examined lymph nodes for removal or sampling for optimized nodal staging recommendation, with a focus on T(1–3)N(0)M(0) patients. METHODS: A total of 55,101 consecutive patients were selected, including 52,099 patients with US Surveillance, Epidemiology, and End Results (SEER) data and 3,002 patients in a Chinese multicenter database from 11 thoracic referral centers, who underwent complete resection plus lymph node dissection or sampling for stage T(1–3)N(0)M(0) NSCLC. Propensity score-matching analysis was performed with R software, and a cut-off value was calculated using X-tile software. Survival was evaluated using the Kaplan-Meier method and Cox proportional hazard models. RESULTS: Five-year survival rates with respect to total examined lymph nodes numbers (examined lymph nodes 10 in each group (P