Association between number of dissected lymph nodes and survival in stage IA non-small cell lung cancer: a propensity score matching analysis

Abstract Background For patients with stage IA non-small cell lung cancer (NSCLC) with tumor size ≤ 2 cm, the prognostic significance of the number of removed lymph nodes (NLNs) through different surgical methods remains unclear. To determine the association of NLNs with cancer-specific survival (CSS) and overall survival (OS) in patients with stage IA NSCLC with tumor size ≤ 2 cm who underwent different lung surgeries. Methods We retrospectively enrolled 7293 patients from the Surveillance, Epidemiology and End Results database. Median NLNs was used to classify the patients into two groups: group A with NLNs ≤ 5 and group B with NLNs > 5. Propensity score matching (PSM) was performed to decrease selection bias. Kaplan–Meier analysis and Cox regression analysis were performed to identify the association between NLNs and survival outcomes. Results Group B had better survival than group A in the unmatched cohort and matched cohort (all P < 0.05). Multivariable analyses revealed that the NLNs significantly affected CSS and OS of eligible cases in the unmatched cohort and matched cohort. Additionally, we found that the NLNs was a protective prognostic predictor of OS for patients who underwent wedge resection, segmental resection, or lobectomy. Conclusion The NLNs was a protective prognostic factor in NSCLC patients with tumor size ≤ 2 cm. We demonstrated that patients with > 5 NLNs in the cohort of wedge resection, segmental resection, or lobectomy exhibited a significantly better OS.