title: Learning curve for percutaneous radiofrequency ablation of pulmonary metastases from colorectal carcinoma: a prospective study of 70 consecutive cases.
abstract: BACKGROUND
  Percutaneous radiofrequency ablation (RFA) for inoperable colorectal pulmonary metastases is associated with a morbidity rate of 30% to 40%. A learning curve in this treatment approach has not been documented before.
  
  
  METHODS
  The clinical and treatment-related data regarding 70 consecutive percutaneous RFA procedures for inoperable colorectal pulmonary metastases were collected prospectively. A comparison between the initial 35 cases (group 1) and the subsequent 35 cases (group 2) was performed. Univariate and multivariate analyses were conducted to identify the significant risk factors for overall morbidity, pneumothorax, and chest drain requirement.
  
  
  RESULTS
  There was no hospital mortality. The overall morbidity rate was 37%. The rate of pneumothorax was 27%. Twelve patients (17%) required chest drain insertion for pneumothorax. There was a significant decline in the incidence of overall morbidity, pneumothorax, and chest drain requirement in group 2 as compared with group 1. Both the number of lung metastases ablated and the RFA treatment period (group 1 vs. group 2) were independent risk factors for overall morbidity, pneumothorax, and chest drain requirement. Distribution of lung metastases (unilateral vs. bilateral) was an independent risk factor for overall morbidity and pneumothorax, but not for chest drain requirement.
  
  
  CONCLUSIONS
  There is a learning curve for percutaneous lung RFA. With accumulated experience in this procedure, a low morbidity rate can be achieved.
authors.affiliation: Department of Surgery, University of New South Wales, St. George Hospital, Sydney, New South Wales, 2217, Australia.
authors.forename: Tristan D
authors.initials: TD
authors.lastname: Yan
authors.forename: Julie
authors.initials: J
authors.lastname: King
authors.forename: Adrian
authors.initials: A
authors.lastname: Sjarif
authors.forename: Derek
authors.initials: D
authors.lastname: Glenn
authors.forename: Karin
authors.initials: K
authors.lastname: Steinke
authors.forename: David L
authors.initials: DL
authors.lastname: Morris
mesh_terms: D000368:Aged; D017115:Catheter Ablation; D002983:Clinical Competence / Q000592:standards*; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D007858:Learning; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013902:Radiography, Thoracic; D015996:Survival Rate; D014057:Tomography, X-Ray Computed