title: Influence of ablative margin on local tumor progression and survival in patients with HCC ≤4 cm after laser ablation.
abstract: BACKGROUND
  Ablation of the normal hepatic parenchyma surrounding the tumor (ablative margin [AM]) is necessary to prevent local tumor progression.
  
  
  OBJECTIVE
  To assess the prognostic value of the ablative margin in patients with HCC ≤4 cm treated with US-guided laser ablation.
  
  
  METHODS
  A cohort of 116 patients (53 women and 63 men, age range 42-82 years) with 132 HCC nodules ≤4 cm completely ablated by US-guided laser ablation was retrospectively analyzed. Rates of local tumor progression were compared using different ablative margin cut-offs (≥2.5, 5.0, 7.5, and 10.0 mm). Survival probability curves were obtained with the Kaplan-Meier method.
  
  
  RESULTS
  The mean period of follow-up was 42 months (range 3-114 months). Local tumor progression was identified in 24 out of 132 lesions (18%), with an average time to progression of 24 months (range 6-36 months). A significant difference in local tumor progression was observed only if the ablative margin was ≥7.5 mm (7% vs. 23%, P = 0.020). Survival curves of patients with or without an ablative margin ≥7.5 mm were not different (P = 0.665; mean survival time 43.8 ± 3.1 and 46.8 ± 6.1 for an AM < or ≥7.5 mm, respectively).
  
  
  CONCLUSIONS
  An ablative margin ≥7.5 mm turned out to be useful in preventing local tumor progression but did not affect long-term survival in patients with HCC ≤4 cm treated with laser ablation.
authors.affiliation: Gastroenterology Department, Diagnostic and Interventional Ultrasound Unit, S Maria della Pietà Hospital, Casoria, Italy. giampierofrancica@gmail.com
authors.forename: Giampiero
authors.initials: G
authors.lastname: Francica
authors.forename: Alesssandra
authors.initials: A
authors.lastname: Petrolati
authors.forename: Enrico
authors.initials: E
authors.lastname: Di Stasio
authors.forename: Sara
authors.initials: S
authors.lastname: Pacella
authors.forename: Roberto
authors.initials: R
authors.lastname: Stasi
authors.forename: Claudio Maurizio
authors.initials: CM
authors.lastname: Pacella
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000601:surgery*; D016009:Chi-Square Distribution; D018450:Disease Progression; D005260:Female; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011336:Probability; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D015996:Survival Rate; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional