title: Long term survival of patients with unsuspected n2 disease in non-small cell lung cancer.
abstract: BACKGROUND
  The aim of this study was to determine the survival rate of patients with non-small cell lung cancer (NSCLC) who were preoperatively diagnosed with a negative N2 lymph node, but postoperatively confirmed as a positive N2 node based on a pathological evaluation.
  
  
  METHODS
  The hospital records of 248 patients from 1994 to 2009 with resected primary NSCLC who were preoperatively diagnosed with negative N2 lymph node, were retrospectively reviewed. Of these, after surgery, there were 148 (59.7%) patients with pathological N0, 54 (21.8%) with pathological N1 and 46 (18.5%) with pathological N2.
  
  
  RESULTS
  The median follow-up period was 24 months (range, 1 to 132 months). The 5-year disease free survival rates were 60% in pN0, 44% in pN1, and 29% in pN2. The 5-year overall survival rates were 63.1% in pN0, 51.9% in pN1, and 33.5% in pN2. There were no statistically significant differences between pN1 and pN2 (p=0.326 and p=0.106, respectively). Thirty-three (71.7%) of the 46 pN2 patients had single-zone metastasis, and 13 patients (28.3%) had multiple-zone metastases over the two nodal zone metastasis. There were no statistical differences in the 5-year disease free survival rate and the 5-year overall survival rates between the two groups.
  
  
  CONCLUSIONS
  The 5-year disease free survival and the overall survival rate of the patients with unsuspected N2 disease were statistically similar with that of the patients with pathological N1 disease. There was no statistically significant difference between the patients with a single-zone metastasis and a multiple zone metastasis.
authors: Department of Thoracic and Cardiovascular Surgery, Keimyung University Dongsan Medical Center, Keimyung University School of Medicine, Korea.
authors: Deok Heon
authors: DH
authors: Lee
authors: Jae Bum
authors: JB
authors: Kim
authors: Dong Yoon
authors: DY
authors: Keum
authors: Ilseon
authors: I
authors: Hwang
authors: Chang Kwon
authors: CK
authors: Park
keywords: Carcinoma, non-small-cell lung; Lymph nodes; Neoplasm staging