Prediction of treatment response following transarterial chemoembolization in patients with HCC using dualtracer positron emission tomography

Abstract

Purpose: While dual-tracer positron emission tomography (DT-PET) with 18F-FDG and 11C-acetate is highly sensitive in detecting HCC, its ability to prognosticate outcomes has not been previously explored. This study aims to evaluate whether DT-PET can predict treatment response in patients with HCC undergoing transarterial chemoembolization (TACE). Material and methods: Patients with HCC who had undergone DT-PET prior to TACE were retrospectively identified. Patient demographics, radiotracer uptake patterns, treatment response as per modified Response Evaluation Criteria In Solid Tumours (mRECIST), progression-free (PFS) and overall (OS) survival were analysed. Results: Between 2015 and 2018, 28 patients (M:F 22:6, median age 64) with 38 target lesions were included. Ten patients had multifocal while 18 had a solitary HCC (median size 19mm). 18F-FDG and 11C-acetate avidities were seen in 37% and 79% of HCC, respectively. Patients who responded to treatment had significantly longer OS (median 47.3 vs 20.9 months, p=0.022) while FDG uptake was associated with shorter PFS (median 2.7 vs 20.8 months, p=0.013) and OS (median 22.3 vs 44.7 months, p=0.008). Baseline raised AFP and multifocal disease were also associated with poorer OS. Lesion-based analysis showed acetate uptake (defined as tumour-to-liver ratio <2 for low or >2 for high) was predictive of treatment response (78% vs 47%, p=0.045). Conclusion: Our study shows that HCC with high acetate uptake is associated with less favourable response to TACE on a per lesion basis while FDG uptake in HCC is associated with shorter PFS and OS. DT-PET can potentially be a novel prognostic biomarker in the era of precision medicine.