Gadoxetic acid uptake as a molecular imaging biomarker for sorafenib resistance in patients with hepatocellular carcinoma: a post hoc analysis of the SORAMIC trial

Purpose: Gadoxetic acid uptake on hepatobiliary phase MRI has been shown to correlate with ß-catenin mutation in patients with HCC, which is associated with resistance to certain therapies. This study aimed to evaluate the prognostic value of gadoxetic acid uptake on hepatobiliary phase MRI in patients with advanced HCC receiving sorafenib. Methods: 312 patients with available baseline hepatobiliary phase MRI images received sorafenib alone or following selective internal radiation therapy (SIRT) within SORAMIC trial. The signal intensity of index tumor and normal liver parenchyma were measured on the native and hepatobiliary phase MRI images, and relative tumor enhancement higher than relative liver enhancement were accepted as high gadoxetic acid uptake, and its prognostic value was assessed using univariate and multivariate Cox proportional hazard models. Results: The median OS of the study population was 13.4 (11.8-14.5) months. High gadoxetic acid uptake was seen in 51 (16.3%) patients, and none of the baseline characteristics was associated with high uptake. In univariate analysis, high gadoxetic acid uptake was significantly associated with shorter overall survival (10.7 vs. 14.0 months, p = 0.005). Multivariate analysis confirmed independent prognostic value of high gadoxetic acid uptake (HR, 1.7 [1.21-2.3], p = 0.002), as well as Child-Pugh class (p = 0.033), tumor diameter (p = 0.002), and ALBI grade (p = 0.015). Conclusion: In advanced HCC patients receiving sorafenib (alone or combined with SIRT), high gadoxetic acid uptake of the tumor on pretreatment MRI, a surrogate of ß-catenin mutation, correlates with shorter survival. Gadoxetic acid uptake status might serve in treatment decision-making process.