Different prognostic significance of examined lymph node count for patients with non-small-cell lung cancer ≤1 cm or >1-2 cm: a population-based study.

Aim: This study aimed to investigate the impact of examined lymph node (ELN) count on survival of resected pT1a-1bN0M0 non-small-cell lung cancer (NSCLC). Materials & methods: Data were extracted from the US Surveillance, Epidemiology and End Results database. The association between ELN count and overall survival (OS) or lung cancer-specific survival (LCSS) was investigated. Results: A total of 9603 patients were enrolled. For the first through the fourth quartiles of pT1aN0M0 group, the 5-year OS and LCSS rates were of no statistical difference. While in pT1bN0M0 group, they were 68.7, 73.8, 76.6 and 77.8% (p < 0.001) and 80.7, 84.1, 85.9 and 87.1% (p < 0.001), respectively. X-Tile analysis showed that 4 is the optimal cutoff value for ELN count in pT1bN0M0 patients for both OS and LCSS. Conclusion: These findings indicated that greater number of ELNs is associated with better survival of resected pT1bN0M0 NSCLC. But a greater number of ELNs is worth to discuss for pT1aN0M0 NSCLC during surgery.