Survival outcome after systematic lymphadenectomy in non-small cell lung cancer according to the latest proposed edition of the TNM system.

BACKGROUND

While systematic lymphadenectomy (SLND) provides critical information for accurate staging, its direct impact on survival outcomes remains unclear and subject to ongoing debate. This study presents survival outcomes across various nodal stages to clarify the potential role of SLND in improving prognosis. SLND is routinely performed during the resection of non-small cell lung cancer (NSCLC) to assess lymph node involvement and determine the nodal stage.

METHODS

We retrospectively analyzed data from 367 patients who underwent curative surgery for NSCLC between 2008 and 2019. The Chi-squared test has been employed to compare the distribution of categorical variables between groups. We used a Cox proportional hazards regression model for multivariable survival analysis to identify independent prognostic factors, including sex, histologic type, N factor, and type of surgical procedure. We evaluated these variables based on 5-year post-surgery survival rates. Additionally, we used the log-rank test and Kaplan-Meier curve analysis.

RESULTS

In 367 patients (228 male and 139 female), SLND was performed. Out of these patients were N0 (n=267, 72.8%), N1 (n=61, 16.6%) and N2 (n=39, 10.6%). The overall 5-year survival rate for the entire cohort was 54.2%. There was a significant difference in survival rates between genders (P<0.001). Females showed a higher survival rate (69.1%) than males (45.2%). The 5-year survival is 66% for stage I (P<0.001) and 33.9% for stage IIA (P<0.001) in NSCLC patients. The multi-level N1 situation did not significantly affect survival (44.4%, P=0.66). The multi-level N2 was associated with a much lower survival rate of 10.0% (P<0.001). An analysis of each lymph node revealed that the paraesophageal group (Group 8) had a survival rate of 14.3% (P<0.001).

CONCLUSIONS

Our study indicates that SLND does not directly impact 5-year survival rates, particularly in early-stage NSCLC. However, SLND may play a critical role in achieving accurate tumor staging, which is essential for guiding subsequent treatment strategies. Despite its utility in staging, the current staging system demonstrates variability in predicting survival outcomes, especially when considering specific N stages or nodal groups involved.