Combination Transarterial Chemoembolization and Stereotactic Body Radiation Therapy for Unresectable Single Large Hepatocellular Carcinoma: Results From a Prospective Phase 2 Trial

Abstract

Patients with hepatocellular carcinoma (HCC) at Barcelona Clinic Liver Cancer (BCLC) early-stage A (BCLC A) not suitable for surgery are first considered for ablation. Nonetheless, objective responses and long-term results for ablation in tumors larger than 3 to 4 cm are suboptimal, creating an unmet clinical need. This phase 2 trial studied combination of transarterial chemoembolization (TACE) and stereotactic body radiation therapy (SBRT) for BCLC A patients with a solitary HCC from 4 to 7 cm. Eligible patients were BCLC A, Child-Pugh score ≤7, Eastern Cooperative Oncology Group performance status 0 presenting with a single HCC from 4 to 7 cm not suitable for resection or liver transplantation. Treatment consisted of 2 sessions of drug-eluting bead-TACE within 1 month followed by immediate SBRT. SBRT delivered 35 to 50 Gy in 5 fractions. The primary endpoint was best objective response rate (ORR) by modified Response Evaluation Criteria in Solid Tumours (mRECIST). Secondary endpoints were overall survival (OS), progression-free survival (PFS), and toxic effects. From 2014 to 2020, 32 were enrolled in a single institution with median follow-up of 37 months. Thirty patients had at least 1 posttreatment scan to assess response. ORR in the target lesion was 91%: 63% complete response (CR; n=20), 28% partial response (n=9), and 3% progression of disease (n=1). Median time to CR was 10.1 months. Median OS was not yet reached and median PFS was 35 months. Patients achieving CR had a trend toward improved PFS (P=.09). Toxic effects were low. This phase 2 trial showed very promising ORR when combining TACE+SBRT in large, unresectable HCC, which translates into excellent OS and PFS. These results provide the rationale for exploring this combination in larger phase 2 and 3 clinical trials and a space where SBRT might offer unique clinical advantage.