Prognostic value of baseline MRI features in patients treated with thermal ablation for hepatocellular carcinoma

Purpose: To investigate prognostic value of baseline MRI features for time-to-recurrence (TTR) and local recurrence in patients with early hepatocellular carcinoma (HCC). Method: Baseline and follow-up images of 88 patients treated with thermal ablation followed by adjuvant sorafenib or matching placebo due to HCC within the phase II prospective randomized trial (SORAMIC) were included. Baseline MRI images were evaluated in terms of atypical enhancement (lack of wash-in or wash-out), lesion diameter, tumor capsule, peritumoral enhancement on arterial phase, intratumoral fat, irregular margin, satellite lesions, and peritumoral hypointensity on hepatobiliary phase. Prognostic value of these features for TTR and local recurrence were assessed with univariable and multivariable Cox proportional hazard models. Results: Recurrence at any location was diagnosed during follow-up in 30 patients, and the median TTR was 16.4 (95% CI, 15 – NA) months. The presence of more than one lesion (p = 0.028) and peritumoral hypointensity on hepatobiliary phase images (p = 0.012) at baseline were significantly associated with shorter TTR in univariable analysis. AFP > 15 mg/dL (p = 0.084), and history of cirrhosis (p = 0.099) were marginally non-significant. Peritumoral hypointensity on hepatobiliary phase images was the only significant risk factor for recurrence in multivariable analysis (p = 0.003). Local recurrence (adjacent to thermal scar) was diagnosed in eleven (8.3%) out of 132 lesions that underwent thermal ablation. The only significant risk factor for local recurrence was a lesion diameter larger than 3 cm (22.2% vs. 4.5%, p = 0.007). Conclusions: Peritumoral hypointensity on hepatobiliary phase can serve as imaging biomarker to identify increased recurrence risk in patients undergoing thermal ablation for early-stage HCC.