title: Learning curve for radiofrequency ablation of liver tumors: prospective analysis of initial 100 patients in a tertiary institution.
abstract: OBJECTIVE
  This study aims to evaluate the effect of operator experience on the treatment outcomes of radiofrequency ablation (RFA) for malignant liver tumors.
  
  
  BACKGROUND
  RFA is gaining popularity as the ablative therapy of choice for liver tumors. It is generally considered a simple and safe technique, and little attention has been paid to the importance of operator experience in this treatment. A learning curve in this treatment modality has not been documented before.
  
  
  METHODS
  The clinical data and treatment outcomes of the initial 100 patients undergoing RFA for liver tumors (hepatocellular carcinoma, n = 84; metastasis, n = 15; cholangiocarcinoma n = 1) were collected prospectively. All patients were managed by a single team of surgeons and interventional radiologists. The data of the first 50 patients (group I) and the second 50 patients (group II) were compared.
  
  
  RESULTS
  RFA was performed by percutaneous (group I, n = 22; group II, n = 19), open (group I, n = 26; group II, n = 30) or laparoscopic (group I, n = 2; group II, n = 1) approach. In group I, 30 patients (60%) had a solitary tumor and 20 (40%) had multiple tumors; in group II, 35 patients (70%) had a solitary tumor and 15 (30%) had multiple tumors (P = 0.295). The size of the largest tumor was comparable between groups I and II (median, 2.8 cm in both groups; P = 0.508). Group II had significantly shorter hospital stay (median, 4.0 versus 5.5 days; P = 0.048), lower morbidity rate (4% versus 16%; P = 0.046) and higher complete ablation rate (100% versus 85.7%; P = 0.006) than group I. There was 1 hospital death (2%) in group I and 0 in group II. By multivariate analysis, treatment period (group I versus group II) was an independent significant factor affecting the morbidity rate and complete ablation rate.
  
  
  CONCLUSIONS
  A low complication rate and a high complete ablation rate could be achieved with the accumulated experience from the first 50 cases of RFA for liver tumors by a specialized team. This study demonstrates that there is a significant learning curve in RFA for liver tumors.
authors.affiliation: Centre for the Study of Liver Disease and Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong, China. poontp@hkucc.hku.hk
authors.forename: Ronnie T
authors.initials: RT
authors.lastname: Poon
authors.forename: Kelvin K
authors.initials: KK
authors.lastname: Ng
authors.forename: Chi Ming
authors.initials: CM
authors.lastname: Lam
authors.forename: Victor
authors.initials: V
authors.lastname: Ai
authors.forename: Jimmy
authors.initials: J
authors.lastname: Yuen
authors.forename: Sheung Tat
authors.initials: ST
authors.lastname: Fan
authors.forename: John
authors.initials: J
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000628:therapy; D017115:Catheter Ablation / Q000592:standards / Q000706:statistics & numerical data; D018281:Cholangiocarcinoma / Q000628:therapy; D002983:Clinical Competence / Q000592:standards* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome