Background: Ablation of the normal hepatic parenchyma surrounding the tumor (ablative margin [AM]) is necessary to prevent local tumor progression.
Purpose: To assess the prognostic value of the ablative margin in patients with HCC ≤4 cm treated with US-guided laser ablation.
Material and 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).
Conclusion: 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.