Toxicity and Dosimetric Parameters of Ablative Radiation Therapy in the Management of Patients with Child-Pugh B/C Liver Function and Unresectable Hepatocellular Carcinoma (HCC).

Purpose/Objective(s) To date there is no clear standard non-surgical therapeutic option for HCC patients. Ablative radiation therapy (SBRT/HIGRT) is an emerging non-invasive treatment for patients with HCC. However, there is concern about the risk for radiation-induced liver toxicity following radiation in patients with decompensated liver function (Child-Pugh B/C). Materials/Methods We retrospectively identified all patients with unresectable, non-metastatic HCC treated with SBRT/HIGRT and underlying Child-Pugh B or C liver function prior to radiation therapy at our University and Veterans Affairs (VA) radiation oncology departments from 2014 to 2019. Primary endpoints included treatment-related toxicity, as well as, evaluation of dosimetric parameters for OAR. Results 38 patients (39 treatment courses) were included. Most patients (97%) had Child-Pugh B7-B9 (62% CP B7, 21% CP B8, 15% CP B9) or ALBI grade 2-3 (69% ALBI grade 2, 31% ALBI grade 3) liver disease prior to radiation therapy. A single patient had Child-Pugh C10 liver function. The most commonly utilized regimens include 50 Gy in either 5 or 10 fractions. The median delivered dose was 50 Gy (range 30-50) in an average of 7.5 fractions (range 5-10). Most patients had a single lesion (63%) with a median lesion size of 3.2 cm (range 1.10-7.40 cm). The mean liver dose was 9.40 Gy (range 3.38-23.94) with a liver D800cc of 4.14 Gy (range 0.35-17.31). All patients completed their intended treatment course with a median follow up of 43 months. Four (10.3%) treatment courses resulted in non-classical radiation-induced liver disease (RILD) (defined as an increase of 2 or more points in Child-Pugh score), compared to 8.3% for patients with Child-Pugh A liver function treated during a similar time period. Otherwise, one patient (2.6%) experienced acute grade 3+ (non-RILD) hepatobiliary toxicity (transient transaminitis). Two-year freedom from local progression was 73% (95% CI 37-90%), median overall survival 12 months (95% CI 5-25 months), and median progression free-survival was not reached. Conclusion Ablative radiation therapy as definitive management for patients with unresectable, non-metastatic HCC appears to be reasonably well tolerated in patients with decompensated liver function at baseline (Child-Pugh B7-B9), with low rates of RILD and encouraging local control. With careful selection, these patients appear to be reasonable candidates for consideration of SBRT/HIGRT. Our analysis did not include enough patients with Child-Pugh C10+ disease to draw meaningful conclusions.