Imaging biomarkers of intrahepatic macrovascular tumour thrombus necrosis after combined therapies for advanced hepatocellular carcinoma: A downstaging indicator for radical surgery

Abstract

\n Background: As novel downstaging therapies are rising and the prevalence of advanced hepatocellular carcinoma (aHCC) with intrahepatic macrovascular tumour thrombus (IMTT) is high, accurate assessment of complete IMTT necrosis after these therapies could lead to an opportunity for subsequent radical surgery. Our preliminary study aimed to analyse the diagnostic accuracy of imaging biomarkers for complete IMTT necrosis after combined therapies for patients with aHCC. Methods: Consecutive patients who were diagnosed with aHCC combined with IMTT at our single institute were treated with combined therapies (immune checkpoint inhibitors, tyrosine kinase inhibitors, or transarterial chemoembolization) and underwent radical surgery. Before and after combined therapies, contrast-enhanced or diffusion-weighted imaging was performed to assess complete IMTT necrosis. Image qualitative biomarkers, including disappearance of arterial enhancement and no diffusion restriction, were analysed. The percentage of IMTT enhancement (IMTTE%) and apparent diffusion coefficient (ADC) values were calculated. Receiver operating characteristic analysis was performed for IMTTE% and ADC values. Complete IMTT necrosis was confirmed by pathologic analysis. Differences were statistically significant when P < 0.05. Results: There were 27 consecutive patients received combined therapies and underwent surgery. Eighteen patients with images from 36 examinations were included. Disappearance of arterial enhancement and no diffusion restriction yielded 88.9%/77.8% sensitivity, 83.3%/80.0% specificity, an 84.2%/82.4% positive predictive value, an 88.2%/75.0% negative predictive value, and 86.1%/78.8% diagnostic accuracy for diagnosing complete IMTT necrosis. The area under curve (AUC) of the IMTTE% values for the diagnosis of viable IMTT was 0.94, with an optimal cut-off value of 145.5% resulting in a sensitivity/specificity of 88.9%/88.9%. The AUC of ADC values for the diagnosis of complete IMTT necrosis was 0.79, with an optimal cut-off value of 1.3×10-3 mm2/s resulting in a sensitivity/specificity of 88.9%/80.0%. Conclusions: Contrast-enhanced and diffusion-weighted imaging biomarkers show good diagnostic performance in the differentiation of complete IMTT necrosis after combined therapies for patients with aHCC.