Stereotactic body radiotherapy (SBRT) is increasingly being used for the treatment of patients with primary or metastatic liver cancer. A single-institution study was conducted to assess the incidence of central hepatobiliary adverse events (AEs) in patients with liver malignancies who were treated with SBRT, and to evaluate the relation with planned dosimetry to define predictors to minimize AEs. The results were presented by Nitika Thawani, Dignity Health Cancer Institute, Phoenix, AZ, at the 2022 ASCO GI Cancers Symposium.
A total of 43 patients with liver cancer who were treated with SBRT between March 2017 and July 2021 were included in the study. Overall, 40 patients were eligible for analysis. Of these, 31 patients had hepatocellular carcinoma, 6 had cholangiocarcinoma, and 3 had metastatic lesions.
Patients received 35 Gy to 50 Gy in 3 to 5 fractions; all patients were prospectively planned with common bile duct spared to a maximum dose of <50 Gy.
All patients had liver function tests at each fraction, and then every 3 months after. The investigators retrospectively contoured central hepatobiliary tree, defined as portal vein from confluence to division, with 1.5-cm margin expansion.
At a median follow-up of 8 months (range, 3-38 months), 35 patients with >3 months of follow-up were evaluated for subacute and chronic AEs. The local control rate at the primary disease site was 85%. The majority (80%) of patients had grade <2 AEs, 7.5% had grade 4 AEs, and 12.5% had grade 3 AEs. Portal-vein thrombosis was reported in 6 (15%) patients. All patients with grade 4 AEs had portal-vein thrombosis or lesion involving the hilum.
The median planning target volume was 241 cc (range, 21.5-1087.5 cc). The median dose was 40 Gy in 5 fractions. Although there was a trend of statistical significance for central hepatobiliary tree V30 and V40 (coeff 0.63), no statistically significant dosimetric association was found.
Based on these data, the investigators concluded that central hepatobiliary AEs occur in 7.5% of patients with liver cancer who are treated with SBRT, and portal-vein thrombosis is associated with an increased risk for such AEs. Moderate doses (30-40 Gy) are a predictor of AEs in patients with liver malignancies and should be limited when planning SBRT, especially in patients with portal-vein thrombosis.
Thawani N, Tan N, Pinnaduwage D, et al. Central hepatobiliary toxicity in patients treated with stereotactic body radiotherapy (SBRT) for liver malignancies. Abstract 409.
To sign up for our newsletter or print publications, please enter your contact information below.
