title: Spontaneous regression of hepatocellular carcinoma: a systematic review.
abstract: OBJECTIVE
  To estimate the actual frequency of spontaneous regression of hepatocellular carcinoma.
  
  
  METHODS
  A systematic review of the literature published during 1978-2007 has been carried out to identify randomized clinical trials of hepatocellular carcinoma that included a control arm receiving either placebo or best supportive care, and in which patients were followed prospectively for tumor response using predefined criteria. Data extraction was conducted independently by two investigators. A meta-analysis to provide a global estimation of regressions in the control arms was performed using an empiric Bayesian random-effects model.
  
  
  RESULTS
  We identified 16 cases of regression (including minor and partial responses) in 10 phase III clinical trials. The rate of spontaneous objective partial regression among patients with hepatocellular carcinoma was 0.406% [95% confidence interval: 0.067-1.043%].
  
  
  CONCLUSIONS
  Although very infrequent, spontaneous regression is not an extraordinary event among patients with hepatocellular carcinoma. Therefore, individual responses to any given therapy should be assessed with caution and this fact may be considered at the time of calculating sample size of pilot clinical trials of new agents.
authors.affiliation: Department of Gastroenterology, Hospital Virgen del Camino, Pamplona, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Oquiñena
authors.forename: Francisco
authors.initials: F
authors.lastname: Guillen-Grima
authors.forename: Mercedes
authors.initials: M
authors.lastname: Iñarrairaegui
authors.forename: Jose M
authors.initials: JM
authors.lastname: Zozaya
authors.forename: Bruno
authors.initials: B
authors.lastname: Sangro
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000473:pathology*; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000473:pathology*; D009365:Neoplasm Regression, Spontaneous; D010919:Placebos; D016032:Randomized Controlled Trials as Topic; D012107:Research Design
chemical_list: D010919:Placebos