Multiparametric quantitative functional MRI for assessing early changes in volumetric functional tumor burden in hepatocellular carcinoma treated by intra-arterial therapies.

Abstract

4114 Background: Hepatocellular carcinoma (HCC) is the most common primary malignant disease of the liver. Intra-arterial therapy (IAT) has been shown to improve survival and is commonly used in unresectable HCC. Assessing response to IAT as early as possible using objective criteria is paramount for clinical care. The purpose of this study was to evaluate volumetric diffusion weighted (DWI) and contrast Enhanced MR imaging (CE-MRI) changes for assessing early treatment response to IAT in hepatocellular carcinoma. Methods: This study included 177 lesions of HCC in 107 patients (85 Male, mean age 64 years) with BCLC A (19) B (44) C (36) D (8) treated by IAT. All patients had pre-IAT and 3-4 weeks follow up MRI with DWI and CE-MR. Tumors were segmented using semi automated software to provide volumetric functional analysis of DWI and CE- MRI as well as percent tumor burden. Statistical analyses include paired t-test, Kaplan-Meier curves, log rank test and multivariate analysis with cox model. Results: There was significant increase in volumetric ADC and significant decrease in volumetric arterial (AE) and venous (VE) enhancement after IAT. Patients with tumor burden of < 10% had improved survival compared to patients with high tumor burden of >10% (log rank p <.008 ) This survival benefit was larger among patients with tumor burden of < 10% who demonstrated an increase in volumetric ADC (>20%. Overall survival (OS) 33.5 mo) and decrease in volumetric VE (>50% OS 35.2 mo) compared to patients with high tumor burden >10% who no favorable response in ADC ( OS 14.1 mo) or VE (OS 16.5 mo) (Log rank p < .001) . In multivariate analysis factors associated with favorable prognosis were: increased ADC, (Hazard Ratio (HR) = 0.44, 95% CI =0.24 - 0.80) decreased VE, (HR = 0.43, 95% CI = 0.22 - 0.84) and BCLC A and B (HR = 0.31, 95% CI =0.18 - 0.54). Conclusions: Volumetric functional analysis of DWI and CE-MR are reliable imaging biomarkers of treatment response and tumor necrosis were able to differentiate responders and non responders. Early assessment of treatment response by volumetric functional MRI predicts prognosis in patients undergoing IAT in HCC.