Assessment of the necessity of interlobar lymph node dissection in pathological stage IB non-small cell lung cancer: a propensity score-matched study

Background Lung cancer is the leading cause of cancer-related deaths worldwide, with non-small cell lung cancer (NSCLC) being the most common type. Systematic lymph node dissection (SLND) is a standard procedure for NSCLC, but the necessity of routine interlobar lymph node dissection (ILND) in early-stage disease, particularly in stage IB NSCLC, remains debated. While ILND can be technically performed, its benefit in improving overall survival (OS) or recurrence-free survival (RFS) is unclear. The need for routine ILND remains controversial, with limited studies addressing its role in early-stage disease. This study aimed to assess whether ILND contributes to better survival outcomes in stage IB NSCLC. Methods We retrospectively analyzed 597 IB-stage NSCLC patients who underwent radical surgery for lung cancer at Sun Yat-Sen University Cancer Center from 1999 to 2009. We used the Cox proportional hazards regression model to analyze prognostic factors. After propensity-score matching (PSM), 458 patients were selected. We applied the Kaplan-Meier method and log-rank test to compare OS and RFS. Results Among 597 patients included in the study, 262 did not have ILND, while 335 did. According to whether the interlobar lymph nodes were dissected, 597 patients were divided into two groups. Significant differences were found between the two groups in laterality, number of dissected lymph node stations, and number of dissected lymph nodes (P < 0.05). Univariate and multivariate Cox analyses by the Cox proportional hazards model showed that age, family history of malignant tumors, and number of dissected lymph nodes were prognostic factors for OS (P < 0.05). For RFS, age and number of dissected lymph nodes were significant (P < 0.05). ILND was not associated with OS or RFS. After PSM, survival analysis using the Kaplan-Meier method and log-rank test showed no statistical association between ILND and OS or RFS (P > 0.05). Conclusion In stage IB NSCLC patients, ILND is not significantly associated with OS or RFS. Routine ILND is not necessary for early-stage NSCLC.