title: Occult nodal metastasis in patients with non-small cell lung cancer at clinical stage IA by PET/CT.
abstract: OBJECTIVE
  The introduction of ¹⁸F-FDG PET/CT has enhanced the diagnostic accuracy of nodal staging for non-small cell lung cancer (NSCLC). We analysed risk factors for occult nodal metastasis in patients with clinical stage IA NSCLC as determined by ¹⁸F-FDG PET/CT.
  
  
  METHODS
  Data for 147 patients diagnosed as clinical stage IA NSCLC by PET/CT from 2005 to 2007 were retrospectively reviewed. All study patients underwent ¹⁸F-FDG PET/CT for lung cancer staging. They also underwent cervical mediastinoscopy or systematic lymph node dissection.
  
  
  RESULTS
  Cervical mediastinoscopy was performed in 78 patients (53.1%), and N2 involvement was detected in 3.8% (3/78) of these patients. Thoracotomy with systematic lymph node dissection was done in 144 patients. Four patients (2.8%, 4/144) were diagnosed with N2 disease after systematic lymph node dissection. Total N2 involvement was 4.8% (7/147). As 9.5% (14/147) of study patients had N1 disease, 14.3% (21/147) of patients had occult nodal (N1 or N2) metastasis. In univariate analyses, larger tumour size and a higher primary tumour maximum standardized uptake value >7.3 (SUV(max)) were associated with occult nodal metastasis. Multivariate analysis demonstrated that a primary tumour SUV(max) >7.3 was an independent predictor of occult nodal metastasis (odds ratio: 7.574; P = 0.001).
  
  
  CONCLUSIONS
  Preoperative PET/CT scans contribute to reduce the frequency of occult nodal metastasis compared with those reported in the pre-PET/CT era. The higher SUV(max) in primary tumour was an independent predictor of occult nodal metastasis in patients with clinical stage IA NSCLC by PET/CT.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kangnam-Gu, Seoul, South Korea.
authors.forename: Hye Kyeong
authors.initials: HK
authors.lastname: Park
authors.forename: Kyeongman
authors.initials: K
authors.lastname: Jeon
authors.forename: Won-Jung
authors.initials: WJ
authors.lastname: Koh
authors.forename: Gee Young
authors.initials: GY
authors.lastname: Suh
authors.forename: Hojoong
authors.initials: H
authors.lastname: Kim
authors.forename: O Jung
authors.initials: OJ
authors.lastname: Kwon
authors.forename: Man Pyo
authors.initials: MP
authors.lastname: Chung
authors.forename: Kyung Soo
authors.initials: KS
authors.lastname: Lee
authors.forename: Young Mog
authors.initials: YM
authors.lastname: Shim
authors.forename: Joungho
authors.initials: J
authors.lastname: Han
authors.forename: Sang-Won
authors.initials: SW
authors.lastname: Um
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008481:Mediastinoscopy; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012307:Risk Factors; D013908:Thoracotomy
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18