title: A system of classifying microvascular invasion to predict outcome after resection in patients with hepatocellular carcinoma.
abstract: OBJECTIVE
  Hepatocellular carcinoma (HCC) recurs in approximately 70% of cases after resection. Vascular invasion by tumor cells can be classified as gross or microscopic (microvascular invasion [mVI]) and is a risk factor for recurrence. We examined a large cohort of patients with HCC who were treated by resection to identify features of mVI that correlated with recurrence and survival.
  
  
  METHODS
  We reviewed the records of all HCC resections performed at the Mount Sinai School of Medicine between January 1990 and March 2006 to identify those with mVI, established by histologic analysis. The numbers and sizes of vessels invaded, invasion of a vessel with a muscular wall, distance from the tumor, and satellite nodules were recorded.
  
  
  RESULTS
  Of the 384 patients who underwent resection for HCC, 131 (34.1%) met the entry criteria. The median follow-up period was 28.9 months. There were 68 recurrences and 54 deaths. In multivariate analysis, invasion of a vessel with a muscular wall predicted recurrence (hazard ratio, 1.8; P = .02), and invasion of a vessel with a muscular wall (hazard ratio, 2.2; P = .018) and invasion of a vessel that was more than 1 cm from the tumor (hazard ratio, 2.1; P = .015) predicted survival. A risk score that assigned points for the presence of each variable correlated with recurrence (P = .028) and survival (P < .0001).
  
  
  CONCLUSIONS
  A novel classification system that includes invasion of a vessel with a muscular wall and invasion of a vessel that is more than 1 cm from the tumor can accurately predict risk of recurrence and survival of patients with mVI after resection of HCC.
authors.affiliation: Mount Sinai Liver Cancer Program, Mount Sinai School of Medicine, New York, New York 10029, USA. sasan.roayaie@mountsinai.org
authors.forename: Sasan
authors.initials: S
authors.lastname: Roayaie
authors.forename: Iris N
authors.initials: IN
authors.lastname: Blume
authors.forename: Swan N
authors.initials: SN
authors.lastname: Thung
authors.forename: Maria
authors.initials: M
authors.lastname: Guido
authors.forename: Maria-Isabel
authors.initials: MI
authors.lastname: Fiel
authors.forename: Spiros
authors.initials: S
authors.lastname: Hiotis
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Labow
authors.forename: Josep M
authors.initials: JM
authors.lastname: Llovet
authors.forename: Myron E
authors.initials: ME
authors.lastname: Schwartz
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000098:blood supply* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D005260:Female; D006498:Hepatectomy; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D012307:Risk Factors; D015996:Survival Rate