title: Significance of the presence of microscopic vascular invasion after complete resection of Stage I-II pT1-T2N0 non-small cell lung cancer and its relation with T-Size categories: did the 2009 7th edition of the TNM staging system miss something?
abstract: BACKGROUND
  The aim of this study was to assess the significance of microscopic vascular invasion (MVI) in a population of resected patients with early-stage non-small cell lung cancer (NSCLC), along with an analysis of the effect of the combination of MVI and tumor size for the T-size categories T1a-T2b according to the 2009 7th edition of the tumor, node, metastasis (TNM) classification.
  
  
  METHODS
  From January 1993 to August 2008, 746 patients with pT1-T2N0 NSCLC received resection at our institution. MVI was ascertained using histopathological and immunohistochemical techniques.
  
  
  RESULTS
  MVI was observed in 257 patients (34%). Prevalence was higher in adenocarcinoma (ADK) than in squamous cell carcinoma (p = 0.002). A significant correlation was found between MVI and ADK (p = 0.03), increased tumor dimension (p = 0.05), and the presence of tumor-infiltrating lymphocytes (p = 0.02). The presence of MVI was associated with a reduced 5-year survival overall (p = 0.003) and in ADK (p = 0.0002). In a multivariate survival analysis, MVI was an indicator of poor survival overall (p = 0.003) and in ADK (p = 0.0005). In each T category (T1a-T2b) of the 2009 TNM staging system, survival of MVI+ patients was significantly lower than the corresponding MVI- patients; T1a and T1b MVI+ patients had a survival similar to MVI- T2 patients.
  
  
  CONCLUSIONS
  The finding of MVI in pT1-T2N0 NSCLC is frequent. MVI correlates with adenocarcinoma histotype, increased tumor dimensions, and tumor-infiltrating lymphocytes. The presence of MVI is an independent negative prognostic factor. In our experience, MVI was a stronger prognostic indicator than T size in T1a-T2b categories according to the 2009 TNM staging system.
authors.affiliation: Division of Thoracic Surgery, University of Torino, Torino, Italy. enrico.ruffini@unito.it
authors.forename: Enrico
authors.initials: E
authors.lastname: Ruffini
authors.forename: Sofia
authors.initials: S
authors.lastname: Asioli
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Filosso
authors.forename: Lucio
authors.initials: L
authors.lastname: Buffoni
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Bruna
authors.forename: Claudio
authors.initials: C
authors.lastname: Mossetti
authors.forename: Paolo
authors.initials: P
authors.lastname: Solidoro
authors.forename: Alberto
authors.initials: A
authors.lastname: Oliaro
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018287:Carcinoma, Large Cell / Q000098:blood supply / Q000473:pathology* / Q000601:surgery; D002289:Carcinoma, Non-Small-Cell Lung / Q000098:blood supply / Q000473:pathology* / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000098:blood supply / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000098:blood supply / Q000473:pathology* / Q000601:surgery; D016246:Lymphocytes, Tumor-Infiltrating / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D019043:Vascular Neoplasms / Q000473:pathology* / Q000601:surgery