Correlation Between the Extent of N1 Lymph Node Station Examination and Prognosis in Stage I Non-small Cell Lung Cancer Patients: One Station is Insufficient.

Abstract

Background: Examination standards for hilar and intrapulmonary (N1) lymph nodes (LNs) have been debated. The objective of this study was to assess the prognostic significance of the extent of examination for N1 LN stations in patients with pathological stage I non-small cell lung cancer (NSCLC).

Methods: A total of 1868 patients were identified and divided into 3 groups on the basis of the number of N1 stations examined: group A (≥3 stations), group B (2 stations) and group C (1 station). Moreover, we investigated the prognostic significance of each individual N1 station examined. The primary outcome was 5-year disease-free survival (DFS).

Results: Overall, 1062, 607, and 199 patients were in groups A, B, and C, respectively. The baseline demographic and clinical characteristics were similar among the groups, except for the tumor side. The 5-year DFS rates were comparable between groups A and B (85.1% vs. 82.7%, P = .3), both of which were significantly greater than that of group C (74.4%) (P < .01). Similar results were observed for the corresponding 5-year overall survival rates. The number of N1 stations examined was an independent predictor in multiple analyses. Additionally, the examination of stations 10 and 13 were independent favorable predictors for 5-year DFS.

Conclusion: For patients with pathological stage I NSCLC, examination of only 1 N1 station is insufficient. Examinations of a minimum of two N1 stations, including stations 10 and 13, is recommended to obtain the optimal survival benefit.