Prognostic impact of lymph node ratio in patients with pT1-2N1M0 non-small cell lung cancer
Sumin Shin1, Danbee Kang2, Jong Ho Cho1
1Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
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.
