title: Lymphatic vessel invasion is a significant prognostic indicator in stage IA lung adenocarcinoma.
abstract: BACKGROUND
  A radical resection is considered to be the most effective treatment for resectable non-small cell lung cancer. However, even when resected in early stages (T1aN0, T1bN0) up to 20% of patients will experience recurrence. The aim of this retrospective study was to evaluate the prognostic influence of lymphatic vessel invasion (LVI) in stage IA adenocarcinoma patients.
  
  
  METHODS
  From January 1983 to June 2003, a total of 229 consecutive patients with pT1a or T1b N0 M0 lung adenocarcinoma who had undergone radical resection and lymph node dissection were retrospectively reviewed. Sections stained by the hematoxylin-eosin and the Elastica van Gieson method were examined for the presence of LVI. The overall survival was estimated using the Kaplan-Meier method, log-rank test, and the Cox proportional hazards analysis.
  
  
  RESULTS
  The median follow-up was 81 months. A total of 143 patients (62%) were able to be diagnosed with regard to the presence of LVI, while information was not provided for 86 patients (38%), who were therefore excluded from the study. LVI was noted in 22 of the evaluable patients (15%) and was not seen in the other 121 patients (85%). The 5-year overall survival rate of the LVI-negative group and the LVI-positive group was 94.5 and 70.9%, respectively (P = .003). A multivariate analysis revealed LVI to be an independent predictive factor (hazard ratio: 0.202; P = .001).
  
  
  CONCLUSIONS
  LVI is an independent poor prognostic factor in patients with pathologic stage IA adenocarcinoma. The T1a and T1b patients with LVI both might benefit from adjuvant chemotherapy.
authors.affiliation: First Department of Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan. kfunai@hama-med.ac.jp
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Funai
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Sugimura
authors.forename: Toyohiko
authors.initials: T
authors.lastname: Morita
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Shundo
authors.forename: Kei
authors.initials: K
authors.lastname: Shimizu
authors.forename: Norihiko
authors.initials: N
authors.lastname: Shiiya
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology* / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D042601:Lymphatic Vessels / Q000473:pathology* / Q000601:surgery; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors