Effect of the number of lymph nodes examined on the survival of patients with stage I non–small cell lung cancer who undergo sublobar resection

Abstract Objective Early stage lung cancer is being detected at a higher frequency with the implementation of screening programs. At the same time, medically complex patients with multiple comorbidities are presenting for surgery, with a concomitant rise in sublobar resection. We sought to examine the impact of sampling lymph nodes on the outcomes of patients undergoing sublobar resection for small ( Methods All patients in the Surveillance, Epidemiology and End Results (SEER) from 2004 -2013 with small ( 9) with both the overall survival (OS) and disease-specific survival (DSS) were examined using univariate as well as multivariate analyses while controlling for covariates such as age, size ( 1cm), grade, histology (adenocarcinoma vs. others) and extent of resection (wedge / segmentectomy). Results Data from 3916 eligible patients were analyzed. 715 (18.3%) patients had segmentectomy. No lymph nodes were examined in 49% and 23% of wedge resection and segmentectomy patients, respectively. Among all eligible patients, 1132 (29%), 474 (12%), 228 (6%) and 328 (8%) patients had 1-3, 4-6, 7-9 and >9 LN examined respectively. Univariate analyses demonstrated significant associations between overall and disease-specific survivals with age, grade, histology, gender, extent of surgery and LNE. The association between the number of lymph nodes examined (LNE) and survival remained significant even after adjusting for significant covariates including extent of sublobar resection (HR for groups with LN 1-3, 4-6, 7-9 and >9 compared to 0 LN examined are 0.79,0.77, 0.68 and 0.45 for OS (P Conclusions Many patients having sublobar resection for early stage NSCLC in the United States do not have a single lymph node removed for pathologic examination. The number of lymph nodes examined is associated with improved survival, presumably due to avoidance of mis-staging. This association seems greater than the association with extent of resection (segmentectomy vs. wedge resection). Appropriate lymph node examination remains an important part of resection for lung cancer even if the resection is sublobar.