title: Thermal ablation of unresectable liver tumors: factors associated with partial ablation and the impact on long-term survival.
abstract: BACKGROUND
  Thermal ablation procedures, including radiofrequency ablation (RFA) or laser-induced interstitial thermotherapy (LITT), are now well established in the treatment of malignant unresectable hepatic tumors. But the impact of partial ablation (PA) on long-term survival following computed tomography (CT)-guided radiofrequency ablation and laser- induced interstitial thermotherapy of unresectable malignant liver lesions and the associated risk factors of PA remain partially unknown.
  
  
  METHODS
  This study included 254 liver tumors in 91 consecutive patients (66 men and 25 women; age 60.9 ± 10.4 years; mean tumor size 25 ± 14 mm [range 5-70 mm]) who underwent thermal ablation (RFA or LITT) between January 2000 and December 2007. Mean follow-up period was 21.1 month (range 1-69 months). Survival rate and local progression-free survival (PFS) were calculated for patients with complete ablation (CA) vs. patients with partial ablation (PA) to assess the impact on long-term survival.
  
  
  RESULTS
  Median survival after CA was 47 months compared to 25 months after PA (P=0.04). The corresponding 5-year survival rates were 44% vs. 20%. Median PFS for CA was 11 months compared to 7 months for PA (P=0.118). The sole statistically significant risk factor for PA was tumor size (>30 mm; P=0.0003). Sustained complete ablation was achieved in 71% of lesions ≤ 30 mm vs. 47% of lesions >30 mm.
  
  
  CONCLUSIONS
  We conclude that achievement of complete ablation is a highly important predictor of long-term survival and that tumor size is by far the most important predictor of the likelihood of achieving complete ablation.
authors.affiliation: Department of Radiology, University Medical Center Regensburg, Regensburg, Germany. philipp.wiggermann@klinik.uni-regensburg.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Wiggermann
authors.forename: Ralf
authors.initials: R
authors.lastname: Puls
authors.forename: Andrej
authors.initials: A
authors.lastname: Vasilj
authors.forename: Dominik
authors.initials: D
authors.lastname: Sieroń
authors.forename: Andreas G
authors.initials: AG
authors.lastname: Schreyer
authors.forename: Ernst-Michael
authors.initials: EM
authors.lastname: Jung
authors.forename: Wojciech
authors.initials: W
authors.lastname: Wawrzynek
authors.forename: Christian
authors.initials: C
authors.lastname: Stroszczynski
mesh_terms: D000368:Aged; D018450:Disease Progression; D005260:Female; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D008113:Liver Neoplasms / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012307:Risk Factors; D015996:Survival Rate