Meta-Analysis Evaluates Y-90 Dosimetry, Tumor Response, and Hepatotoxicity
AUSTIN, TX—A systemic review and meta-analysis has found that an average tumor dose of 275 Gy for patients with hepatocellular carcinoma (HCC) treated with Y-90 radioembolization is able to predict objective tumor response.
The authors undertook the review and analysis to better understand Y-90 radioembolization dosimetry and how dose relates to tumor response and hepatotoxicity. There were a total of 22 studies included in the analysis. Included studies were peer-reviewed and human-only. Additonally, included studies were required to show absorbed radiation by tumor involved and/or non-tumoral liver (NTL) determined in a quantifiable manner, and tumor response needed to be measured with accepted clinical imaging criteria and/or hepatic toxicity reported by Common Terminology Criteria for Adverse Events (CTCAE). The researchers performed meta-analysis of data from the included studies in order to find associated pooled average doses.
There were 4 studies with data suitable for meta-analysis for hepatic toxicity, and 3 studies with data for HCC total response dosimetry. “Importantly, this meta-analysis included both glass and resin microspheres,” said Daniel Mir, MD, in an oral abstract presentation.
The study was limited by data heterogeneity, he said, but the results corroborate those of studies not included in the meta-analysis, such as a tumoricidal dose of greater than 120 Gy for resin microspheres and greater than 205 Gy for glass microspheres. Dr Mir also noted that the literature consistently supports that resin and glass microspheres produce treatment response and hepatotoxicity at different doses, a finding that was seen in the meta-analysis.
Regarding dosimetry, Y-90 PET/CT dosimetry literature identifies a safe dose of less than 70 Gy for the non-tumoral liver, and this was consistent with the findings of the meta-analysis. The meta-analysis also corroborated the literature in that PET-CT metabolic profiling predicts tumor radiosensitivity.
Results from the meta-analysis of data across 179 patients revealed that 97.9 Gy was the average dose to non-tumoral liver linked with CTCAE grade 2 or greater hepatic toxicity versus 71.8 Gy for those without. Using data from 218 patients, the meta-analysis showed that an average tumor dose of 275 Gy was associated with an objective tumor response compared with 143.4 Gy for those with no response. “Significant hepatotoxicity is unlikely if ≤70 Gy is delivered to surrounding non-tumoral liver,” the study’s authors concluded.
Mir DIA, Risk BB, Cronan J, et al. Defining the relationship between radiation dose, tumor response and associated liver toxicity in hepatocellular carcinoma after Y90 radioembolization: a systematic review and meta-analysis. Abstract 116. Society of Interventional Radiology meeting. Presented on March 24, 2019.