Prognostic impact of lymph node ratio in patients with pT1-2N1M0 non-small cell lung cancer

Sumin Shin ¹, Danbee Kang ², Jong Ho Cho ¹, Yong Soo Choi ¹, Jhingook Kim ¹, Jae Ill Zo ¹, Young Mog Shim ¹, Hong Kwan Kim ¹

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• PMID: 33209388 
• PMCID: PMC7656357 
• DOI: 10.21037/jtd-20-1611

Free PMC article

Abstract

Background: This study evaluated the lymph node ratio (LNR) defined as the ratio of the number of metastatic lymph nodes to the number of dissected lymph nodes as a prognostic factor for survival in patients with pT1-2N1M0 non-small cell lung cancer (NSCLC).

Methods: We retrospectively reviewed 413 patients with pathologic T1-2N1M0 NSCLC after complete surgical resection and mediastinal LN dissection between January 2004 and December 2012. The cut-off value for LNR was determined using χ² tests, which were calculated using Cox proportional hazards regression model. Based on this model, the optimal cut-off value for LNR was 0.1.

Results: The study included 337 males and 76 females with a mean age of 62 years (range, 34-83 years). Patients with a high LNR (≥0.1) were more likely to be female and have more adenocarcinomas compared with patients with a low LNR (<0.1). The overall survival (OS) and disease-free survival (DFS) rates were significantly worse in the high LNR group than the low LNR group (OS, 55.4% vs. 69.8%, respectively P=0.003; DFS, 33.2% vs. 61.7%, P<0.001). In the multivariate analysis, a high LNR was associated with significantly worse OS [adjusted hazard ratio (aHR), 2.69; 95% confidence interval (CI), 1.74-4.17] and DFS (aHR, 2.41; 95% CI, 1.57-3.68).

Conclusions: LNR is an independent prognostic factor for survival in patients with pT1-2N1M0 NSCLC. These findings may provide useful prognostic information to allow the selection of patients for more aggressive postoperative therapy or follow-up strategies.

Keywords: Lung neoplasm; lymph nodes; non-small cell lung cancer (NSCLC); prognosis; risk factors.