Supplementary Material for: Early versus late recurrence of hepatocellular carcinoma after microwave ablation: patterns, treatments, and post-recurrence survival

Introduction Recurrence after microwave ablation (MWA) has not been extensively studied. We aimed to investigate the patterns, treatments, and survival of patients with hepatocellular carcinoma (HCC) who experienced early and late recurrence after MWA.
Methods This retrospective study included patients with HCC recurrence after MWA as the initial treatment from January 2008 to December 2021. Recurrence patterns, treatments, and outcomes between patients with early and late HCC recurrence were compared. Prognostic factors of post-recurrence survival (PRS) were identified by multivariable Cox regression analyses.
Results Among 222 patients, 128 developed early recurrence (≤2 years after MWA) and 94 had late recurrence (>2 years). Majority of the recurrent HCC were intrahepatic-only recurrence, within the Milan criteria, and received potentially curative treatment. No significant differences in the recurrence patterns, vascular invasion, tumor staging, post-recurrence treatments or median PRS (35.0 vs 33.0 months, p=0.523) were identified between patients with early and late recurrence. Multivariable analyses suggested that multiple tumor number (hazard ratio (HR), 1.54; 95% CI: 1.03-2.30, p=0.038), extra-hepatic recurrence (HR, 2.14, 95% CI: 1.16-3.92, p=0.015), vascular invasion (HR, 2.37, 95% CI: 1.18-4.76, p=0.038) and higher ALBI grade (HR, 2.18, 95% CI: 1.54-3.08, p<0.001) were independent risk factors of worse PRS, while curative treatment after recurrence (HR, 0.59, 95% CI: 0.38-0.92, p=0.038) was associated with better PRS.
Conclusions No differences in recurrence patterns, post-recurrent treatments or PRS were found between HCC patients with early and late recurrence following MWA. Tumor burden and patients’ liver function reserve should be considered to decide the optimal post-recurrence treatment after MWA.