title: Intrahepatic recurrence after percutaneous radiofrequency ablation of hepatocellular carcinoma: analysis of the pattern and risk factors.
abstract: OBJECTIVE
  To evaluate the pattern and risks for intrahepatic recurrence after percutaneous radiofrequency (RF) ablation for hepatocellular carcinoma (HCC).
  
  
  METHODS
  We studied 62 patients with 72 HCCs (< or =4 cm) who were treated with percutaneous RF ablation. The mean follow-up period was 19.1 months (6.0-49.1). We assessed the incidence and cumulative disease-free survival of local tumor progression (LTP) and intrahepatic distant recurrence (IDR). To analyze the risk factors, we examined the following, for the LTP: (1) tumor diameter, (2) contact with vessels, (3) degree of approximation to hepatic hilum, (4) contact with hepatic capsule, (5) presence of ablative safety margin, (6) degree of benign periablational enhancement and (7) serum alpha-fetoprotein; for the IDR: (1) severity of hepatic disease, (2) presence of HBsAg, (3) serum alpha-fetoprotein, (4) whether RF ablation was the initial treatment and (5) multiplicity of tumor for IDR.
  
  
  RESULTS
  The incidence of overall recurrence, LTP and IDR was 62.9%, 26.4% and 53.2%, respectively. The cumulative disease-free survival rates were 52%, 82% and 56% at 1 year, 26%, 63% and 30% at 2 years, respectively. Univariate analysis showed that the significant risk factors for LTP were: a tumor with a diameter >3 cm, contact of HCC with a vessel and an insufficient safety margin (p<0.05). A multivariate stepwise Cox hazard model showed that the measurement of a tumor diameter >3 cm and insufficient safety margin were independent factors. Only the increased serum alpha-fetoprotein was a significant risk factor for IDR (p<0.05).
  
  
  CONCLUSIONS
  Intrahepatic recurrence after percutaneous RF ablation is common. Large HCC (>3 cm) with high serum alpha-fetoprotein should be treated more aggressively because of higher risk for recurrence.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, South Korea.
authors.forename: Young-sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Hyunchul
authors.initials: H
authors.lastname: Rhim
authors.forename: On Koo
authors.initials: OK
authors.lastname: Cho
authors.forename: Byung Hee
authors.initials: BH
authors.lastname: Koh
authors.forename: Yongsoo
authors.initials: Y
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000473:pathology* / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015994:Incidence; D008113:Liver Neoplasms / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D016016:Proportional Hazards Models; D012307:Risk Factors