The extent of mediastinal lymph node dissection correlates with survival of small cell lung cancer patients after resection: a propensity score-matched cohort study analysis

Background: Evidence on the importance of lymph node (LN) dissection during resection for small cell lung cancer (SCLC) is scarce. This study sought to investigate the clinical impact of the extent of lymphadenectomy on the survival of patients with SCLC. Methods: Patients who underwent resection for primary SCLC between 2000 and 2016 were identified from the Surveillance, Epidemiology, and End Results (SEER) cancer registry. The patients were stratified based on the number of LNs dissected (0, 1-3, 4-11, and >= 12) via an X-Tile software analysis, and lung cancer-specific survival (LCSS) and overall survival (OS) were compared between these stratified groups using Kaplan-Meier curves. A propensity score-matched analysis and a Cox regression model were used to adjust for potential confounders. Results: A total of 1,883 patients with SCLC met our criteria and were enrolled in the study. The LCSS and OS analyses revealed that patients who underwent IN dissection during surgery had longer survival times significantly than patients who did not. Similarly, patients who underwent more extensive LN dissection (>= 14 LNs) had longer survival times than those who underwent less extensive LN dissection (1-3 LNs). However, no significant increase in survival time was found for patients who underwent the dissection of >= 12 LNs compared to those who underwent the dissection of 4-11 LNs. These results were confirmed in our propensity-matched and Cox regression analyses. Conclusions: Our study revealed that patient survival after surgical resection for SCLC is associated with the number of dissected LNs, and the number of LNs for dissection ranges from 4 to 11 achieve the best survival outcome.