title: Prognosis of unexpected and expected pathologic N1 non-small cell lung cancer.
abstract: BACKGROUND
  This study was undertaken to compare clinicopathologic features and survival between patients with unexpected N1 (clinical N0-pathologic N1) and expected N1 disease (clinical N1-pathologic N1) after operation for non-small cell lung cancer.
  
  
  METHODS
  From 2003 to 2009, 305 patients who were found to have pathologic N1 disease after complete resection were retrospectively analyzed. Among these, 177 patients had negative findings for both computed tomography (CT) and positron emission tomography (PET)/CT (group cN0). Sixty-eight patients had negative CT and positive PET/CT or positive CT and negative PET/CT findings (group cN0-1). Sixty patients had positive findings for both CT and PET/CT (group cN1).
  
  
  RESULTS
  Patients in the cN1 group had larger tumors (p<0.001), greater pathologic T stage (p=0.018), and greater percentage of squamous cell carcinoma (p<0.001) than did those in the other groups. Patients in the cN1 group had a greater number of positive N1 lymph nodes (p=0.004) and more frequent extracapsular nodal invasion (p<0.001). The 5-year overall survival was 66%, 63%, and 58% in groups cN0, cN0-1, and cN1, respectively (cN0 vs cN0-1, p=0.958; cN0 vs cN1, p=0.038). The 5-year disease-free survival was 54%, 52%, and 39% in groups cN0, cN0-1, and cN1, respectively (cN0 vs cN0-1, p=0.862; cN0 vs cN1, p=0.01).
  
  
  CONCLUSIONS
  Patients with unexpected N1 disease showed better survival than did those with expected N1 disease, which seemed to be related to the pathologically minimal extent of the primary tumor and nodal involvement.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sumin
authors.initials: S
authors.lastname: Shin
authors.forename: Hong Kwan
authors.initials: HK
authors.lastname: Kim
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Choi
authors.forename: Kwhanmien
authors.initials: K
authors.lastname: Kim
authors.forename: Jhingook
authors.initials: J
authors.lastname: Kim
authors.forename: Young Mog
authors.initials: YM
authors.lastname: Shim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D008197:Lymph Node Excision / Q000379:methods; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D011013:Pneumonectomy / Q000379:methods; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: 10