Does the extent of lymph nodes dissection affect the prognosis of resected stage IA non-small cell lung cancer?

Purpose: Curative surgery remains the priority for treatment of stage IA non-small cell lung cancer (NSCLC). The purpose of this study is to investigate if the extent of lymph node (LN) dissections affect the prognosis of resected stage IA NSCLC.

Methods: A total of 110 stage IA NSCLC patients who underwent curative resections were reviewed. The patients were classified according to the number of lymph nodes dissected (N) and levels sampled (NL, N2). The tumor residuals of 2,251 LNs were detected by immunohistochemistry (IHC). The Flow Cytometry (FACS) of the peripheral blood (PB) and LNs was used to evaluate patients' immunity. The relationship between the studied factors and the correlation with disease-free survival (DFS) was analyzed.

Results: Disease free survival was improved as the extent of dissections increased in terms of N, NL and N2 (p = 0.005, <0.001, <0.001). Multivariate tests suggested N, N2 and NL (p = 0.001, 0.001, <0.001) were independent risk factors. However, the detection of tumor residuals also increased with the extent of dissection (p = 0.023, <0.001) while the presence of micrometastasis (MM) correlated with poor DFS (p = 0.028). Increased N represented weakened innate immunity (p = 0.048). Multivariate tests did not indicate a correlation between immunity and patients' DFS (p = 0.074).

Conclusion: The more extensive lymph node dissections achieved better disease control for stage IA NSCLC. Greater retrieval of LNs did not imply enhanced innate immunity; nor did their immunity level affect survival.