title: Prognostic impact of microscopic vessel invasion and visceral pleural invasion in non-small cell lung cancer: a retrospective analysis of 2657 patients.
abstract: OBJECTIVE
  We aimed to assess the prognostic significance of microscopic vessel invasion (MVI) and visceral pleural invasion (VPI) in non-small cell lung cancer (NSCLC).
  
  
  BACKGROUND
  VPI is included in the current tumor-node-metastasis (TNM) classification in NSCLC; however, MVI is not incorporated in TNM classification.
  
  
  METHODS
  From August 1992 to December 2009, 2657 consecutive patients with pathological T1-4N0-2M0 NSCLC underwent complete resection. In addition to conventional staging factors, we evaluated MVI histologically and analyzed its significance in NSCLC recurrence prognosis. The recurrence-free period in several NSCLC subgroups was analyzed using the Kaplan-Meier method and Cox regression analysis.
  
  
  RESULTS
  The proportion of patients with a 5-year recurrence-free period was 52.6% and 87.5%, respectively, in those with and without MVI (P < 0.001). Multivariate analysis showed that MVI, similarly to VPI, was found to be an independently significant predictor of recurrence [hazard ratio (HR): 2.78]. In particular, MVI and VPI were the 2 strongest significant independent predictors of recurrence in 1601 patients with pathological stage I disease treated without adjuvant chemotherapy (HR: 2.74 and 1.84, respectively). In each T subgroup analysis, evident and significant separation of the recurrence-free proportion curves were observed among the 3 groups (VPI and MVI absent, VPI or MVI present, and VPI and MVI present).
  
  
  CONCLUSIONS
  This study demonstrated that MVI was a significant independent risk factor for recurrence in patients with a resected T1-4N0-2M0 NSCLC. Further data on MVI prognostic impact should be collected for the next revision of the TNM staging system.
authors.affiliation: *Division of Thoracic Surgery, National Cancer Center Hospital East †Pathology Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Neri
authors.forename: Junji
authors.initials: J
authors.lastname: Yoshida
authors.forename: Genichiro
authors.initials: G
authors.lastname: Ishii
authors.forename: Yuki
authors.initials: Y
authors.lastname: Matsumura
authors.forename: Keiju
authors.initials: K
authors.lastname: Aokage
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Hishida
authors.forename: Kanji
authors.initials: K
authors.lastname: Nagai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D010994:Pleura / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate