title: Topographical impact of hepatitis B-related hepatocellular carcinoma on local recurrence after radiofrequency ablation.
abstract: BACKGROUND
  Radiofrequency ablation (RFA) is an efficient and safe treatment modality for early-stage hepatocellular carcinoma (HCC). However, its application is sometimes limited by several topographical factors. Whether topographical characteristics are risk factors for local recurrence after RFA is still under debate.
  
  
  OBJECTIVE
  The aims of this study were to identify topographical risk factors for the local recurrence of solitary HCC after RFA and to evaluate their impact on long-term treatment outcomes.
  
  
  METHODS
  The clinical and radiologic findings of patients with solitary hepatitis B virus (HBV)-related HCC<4.0 cm undergoing RFA were retrospectively reviewed. The Cox regression model was used to identify risk factors that predicted local recurrence.
  
  
  RESULTS
  A total of 300 patients with solitary, HBV-related HCC were included in this retrospective cohort study. Seventy patients (23.3%) experienced local recurrence after RFA during the median follow-up duration of 43.0 months (range, 3.0 to 69.0 mo). Multivariate analysis showed that tumor size ≥2.0 cm [hazard ratio (HR), 1.716; P=0.047], proximity to a large vessel (HR, 2.609; P=0.024), and proximity to the diaphragm (HR, 3.128; P=0.004) were independent predictors of the local recurrence of solitary HCC. Moreover, the cumulative risk of local recurrence after RFA increased with the number of risk factors.
  
  
  CONCLUSIONS
  Proximity of HCC to a large vessel or the diaphragm as well as large tumor size may increase the risk of local recurrence after RFA. Therefore, the topographical factors of HCC should be considered to tailor therapeutic decisions for solitary, HBV-related HCC.
authors.affiliation: *Department of Internal Medicine, Dongnam Institute of Radiological & Medical Sciences Departments of †Internal Medicine ‡Radiology, Seoul Metropolitan Government Seoul National University Boramae Medical Center §Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Joon Suk
authors.initials: JS
authors.lastname: Kim
authors.forename: Won
authors.initials: W
authors.lastname: Kim
authors.forename: Young Ho
authors.initials: YH
authors.lastname: So
authors.forename: Su Jong
authors.initials: SJ
authors.lastname: Yu
authors.forename: Byeong Gwan
authors.initials: BG
authors.lastname: Kim
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000601:surgery* / Q000821:virology; D017115:Catheter Ablation / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006509:Hepatitis B / Q000150:complications*; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000601:surgery* / Q000821:virology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local; D016016:Proportional Hazards Models; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors