title: Heterogeneity of clinical n1 non-small cell lung cancer.
abstract: BACKGROUND
  There have been many reports of N1 node metastasis on computed tomography (CT) scan, but not on positron emission tomography (PET)-CT in nonsmall cell lung cancer. The aim of this study was to analyze the clinicopathologic correlation and survival of N1 disease on preoperative PET-CT.
  
  
  METHODS
  From January 2003 to December 2007, 1,748 curative lung resections were performed at a single institute. We enrolled 91 patients with clinical N1 on PET-CT. All the enrolled patients had undergone pulmonary resection with mediastinal lymph node dissection. According to the preoperative PET-CT, we classified the patients into two groups: those with single N1 metastasis (cN1a, n = 91) and those with multiple N1 metastases (cN1b, n = 8). Clinicopathologic N staging was compared and survival analysis was performed.
  
  
  RESULTS
  Pathologic N2 was found in 19 (19%) patients and was more common in cN1b (4 of 8) than in cN1a group (15 of 91) (p = 0.042). Overall or disease-free survival rate was not different between cN1a and cN1b in the pathologic non-N2 (p = 0.723, 0.905) or in pathologic N2 (p = 0.954, 0.607) subgroups.
  
  
  CONCLUSIONS
  Clinical N1 on PET-CT is heterogeneous in its pathologic staging and multiple clinical N1 is more related to pathologic N2 than single clinical N1. More cases are needed to show the prognostic significance of multiple clinical N1-pathologic N2.
authors: Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Dohun
authors: D
authors: Kim
authors: Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Yong Soo
authors: YS
authors: Choi
authors: Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Hong Kwan
authors: HK
authors: Kim
authors: Department of Thoracic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea.
authors: Kwhanmien
authors: K
authors: Kim
authors: Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Jhingook
authors: J
authors: Kim
authors: Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Young Mog
authors: YM
authors: Shim
mesh_terms: D001706:Biopsy; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000401:mortality / Q000556:secondary*; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008481:Mediastinoscopy; D008482:Mediastinum; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011013:Pneumonectomy; D049268:Positron-Emission Tomography; D057234:Preoperative Period; D011379:Prognosis; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D014057:Tomography, X-Ray Computed