Purpose/Objective: To report on a single-arm prospective clinical trial (NCT03896646) on 90Y-glass radioembolization (RE) for hepatocellular carcinoma (HCC) patients using patient-specific voxel-dosimetry treatment planning. The primary endpoint is localized mRECIST objective response rate (ORR) at 6-month follow-up.
Materials & Methods: A single-institution 40 patient IRB-approved prospective clinical trial was opened in 9/2019. Eligibility criteria included adult HCC patients eligible for RE with non-infiltrative tumors ≥3 cm. Patients underwent hepatic angiography with Angio CT , received 99mTc-MAA injections at all planned sites of treatment, and were imaged with MAA SPECT/CT. Patient specific voxel dosimetry based treatment plans with tumor mean dose (Dmean) ≥200 Gy and normal liver Dmean ≤100 Gy were created. Treatment of ≤2 segments could be based on single-compartment dosimetry with Dmean ≥200 Gy. Post RE imaging for dose verification was performed using both 90Y SPECT/CT and 90Y PET/CT. Tumor responses (localized mRECIST) and overall toxicities (CTCAE 5.0) were determined 3 and 6 months post-RE.
Results: 40 patients received therapy, and 37 patients completed 6-month follow-up. The median treated index lesion size was 5.3 cm (3.0 to 15.4). The tumor Dmean was 326 Gy (212 to 843). The ORR was 96% (46/48), with 58% (28/48) CR, 38% (18/48) PR and 4% (2/48) SD. Two patients experienced one nontreatment-related grade 3 toxicity. One patient developed duodenal ulcer with grade 5 toxicity. Doses were strongly correlated between (1) pre-therapy MAA and post-therapy 90Y with R2=0.93 and equivalent (±20%) in 96% of cases; and (2) post-therapy 90Y-SPECT and 90Y-PET with R2=0.96 and equivalent (±20%) in 87% of cases.
Conclusion: RAPY90D trial has demonstrated the feasibility and clinical benefits of prospective, MAA-based, patient-specific voxel dosimetry treatment planning for 90Y RE of HCC. RE treatment plans targeting high dose to tumors (≥200 Gy) and minimizing dose to normal liver resulted in 96% tumor response rates.
