Non-transplantable recurrence after percutaneous thermal ablation of ≤3-cm HCC: Predictors and implications for treatment allocation

Percutaneous thermal ablation (PTA), resection, and liver transplantation are the standard curative options for hepatocellular carcinoma (HCC). Liver transplantation yields the best long-term outcomes but is limited by graft shortage. Thus, patients with <= 3-cm HCC are primarily treated by PTA even though recurrence is frequent and may occur outside transplant criteria. Data on non-transplantable recurrence (NTR) following PTA are lacking, however. We therefore investigated the incidence and predictors of NTR among 213 potentially transplantable patients (cirrhosis, 93%; Child-Pugh A, 98.6%; alcohol-related disease, 62%) with <= 3-cm HCC(s) treated by PTA, to stratify them according to their NTR risk and to improve treatment allocation. During follow-up (median: 41.2 months), NTR occurred in 18.3% (alpha-fetoprotein [AFP] model) and 23% (Milan) patients. NTR prediction with competing-risk analysis and internal validation revealed AFP > 100 ng/ml (subdistribution hazard ratio: 7.28; p < 0.001) and prior HCC (subdistribution hazard ratio: 3.77; p = 0.002) as independent predictors (Harrell's C: 0.76). Based on this model using the AFP score (equally predictive within Milan criteria), patients were stratified into three NTR risk categories: HCC-naive with AFP < 100 ng/ml (low risk, n = 108 of 213), non-HCC naive with AFP < 100 ng/ml (intermediate risk, n = 92 of 213), AFP >= 100 ng/ml (high risk, n = 13 of 213), among whom 9.3% (3.7% [Milan]), 22.8% (25% [Milan]), and 61.5% (38/5% [Milan]) presented NTR (p < 0.001). Median recurrence-free survival was 4.6, 14.5, and 43.4 months, respectively, in high-risk, intermediate-risk, and low-risk categories (p < 0.001). Median overall survival, which was 19.1 months in high-risk patients, was not reached otherwise (p < 0.001). Conclusion: Overall, PTA of <= 3-cm HCC incurs a low NTR risk. Simple and noninvasive predictors (HCC naivety, AFP) accurately stratified patients' risk of NTR, and should help to improve treatment allocation. Patients with AFP >= 100 ng/ml have a high risk of NTR, poor recurrence-free survival, and overall survival. Further studies evaluating preemptive transplantation or adjuvant/neoadjuvant strategies are highly needed in this small patient subset.