High impact of macroaggregated albumin-based tumour dose on response and overall survival in hepatocellular carcinoma patients treated with 90 Y-loaded glass microsphere radioembolization.

Background & Aims: Efficacy of radioembolization is derived from radioinduced damage, whereas tumour dosimetry is not considered as yet in prospective clinical trials.

Objectives: This study evaluates the impact of tumour dose (TD), based on 99m Tc macroaggregated albumin (MAA) quantification, on response and overall survival (OS). Materials and

Methods: We consecutively included 85 patients with hepatocellular carcinoma treated with 90 Y-loaded glass microspheres. TD was calculated using a quantitative analysis of the MAA SPECT/CT. Responses were assessed after 3 months using the European Association for the Study of the Liver criteria. OS was assessed using Kaplan-Meier tests.

Results: Response rate was 80.3% on lesion-based analysis (n=132), and 77.5% on patient-based analysis. The response rate was only 9.1% for patients with TD <205 Gy against 89.7% for those with TD ≥205 Gy (P<10-7 ). Non-portal vein thrombosis (PVT) patients exhibited a median OS of 11.75 m (95% CI: 3-30.7 m) for TD <205 Gy, and 25 m (95% CI: 15-34.7 m) for TD ≥205 Gy (P=.0391). PVT patients exhibited a 4.35 m median OS (95% CI: 2-8 m) for TD<205 Gy, and 15.7 m (95% CI: 9.5-25.5 m) for TD ≥205 Gy, (P=.0004), with HR of 6.99. PVT patients exhibited a median OS of 3.6 m (95% CI: 2-8 m) when PVT MAA targeting was poor or with TD <205 Gy (poor candidate), vs 17.5 m (95% CI: 11-26.5 m) for the others identified as good candidates (P<.0001), with HR of 12.85.

Conclusion: This study confirms the highly predictive value of MAA-based TD evaluation for response and OS. TD evaluation and PVT MAA targeting should be further evaluated in ongoing trials, whereas personalized dosimetry should be implemented in new trial designs.