title: Clinical significance of microscopic tumor venous invasion in patients with resectable hepatocellular carcinoma.
abstract: BACKGROUND
  Tumor venous invasion in patients with resectable hepatocellular carcinoma (HCC) is frequent and can be macroscopic and microscopic or microscopic alone. Although macroscopic invasion is a well-established prognostic indicator, the clinical significance of microscopic invasion remains unclear.
  
  
  METHODS
  There were 322 patients enrolled who had undergone curative resection for HCC. The clinicopathologic factors and prognostic significance associated with macroscopic and microscopic venous invasion were analyzed.
  
  
  RESULTS
  Macroscopic invasion was observed in 50 patients (15.5%) and microscopic invasion in 190 (59.0%). The larger the tumor, the more the incidence of venous invasion. There were 140 patients with microscopic invasion only (Group 1). Patients with macroscopic invasion (Group 2, n = 50) also had microscopic invasion. Compared with patients without venous invasion (Group 3, n = 132), Group 1 had a higher alpha-fetoprotein level, a larger tumor size, and more tumors without encapsulation. For group 1, the 1-, 3-, and 5-year disease-free survival rates were 65.6%, 41.6%, and 30.8%, respectively. The 1-, 3-, and 5-year overall survival rates were 87. 8%, 60.0%, and 52.7%, respectively. The survival rates of group 1 were lower than those of group 3 and higher than those of group 2 (P <.05). Multivariate analysis indicated that microscopic and macroscopic venous invasion, surgical margin, indocyanine-green retention, and tumor size and number were significant predictors of postresectional survival.
  
  
  CONCLUSIONS
  In HCC patients, microscopic venous invasion is frequent and related independently to postresectional outcome.
authors.affiliation: Department of Surgery, Veterans General Hospital-Taipei, and the College of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.
authors.forename: T J
authors.initials: TJ
authors.lastname: Tsai
authors.forename: G Y
authors.initials: GY
authors.lastname: Chau
authors.forename: W Y
authors.initials: WY
authors.lastname: Lui
authors.forename: S H
authors.initials: SH
authors.lastname: Tsay
authors.forename: K L
authors.initials: KL
authors.lastname: King
authors.forename: C C
authors.initials: CC
authors.lastname: Loong
authors.forename: C Y
authors.initials: CY
authors.lastname: Hsia
authors.forename: C W
authors.initials: CW
authors.lastname: Wu
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000473:pathology* / Q000556:secondary*; D005260:Female; D006503:Hepatic Veins / Q000473:pathology; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011169:Portal Vein / Q000473:pathology