Dose delivery estimated by bremsstrahlung imaging and partition model correlated with response following intra-arterial radioembolization with 32P-glass microspheres for the treatment of hepatocellular carcinoma.

RATIONALE: The objective of this study was to retrospectively evaluate the efficacy of a combination of (32)P-glass microsphere-mediated intra-arterial internal radiation and chemoembolization for the treatment of hepatocellular carcinoma.
METHODS: Twenty-five consecutive patients with primary hepatocellular carcinoma referred for radiation therapy were treated with intra-arterial infusion of (32)P-glass microspheres followed by chemoembolization. beta-bremsstrahlung imaging was performed to monitor microsphere distribution. A partition model and a radiation dose equation were used for determination of radiation exposure in various tissues. Clinical response was evaluated using computed axial tomography scans.
RESULTS: The mean estimated absorption dose in tumor tissue was 137.42 +/- 56.69 Gy. A receiver operating characteristic curve was used to establish 90.65 Gy as the cutoff absorption dose with the best sensitivity and specificity for predicting response. The overall tumor response rate was 92%, while response in patients with radiation doses >90.65 Gy was 100%. Overall median patient survival was 15 months.
CONCLUSION: beta-bremsstrahlung imaging following intra-arterial infusion of (32)P-glass microspheres and chemoembolization incorporates effective treatment with convenient dosimetry monitoring and manageable adverse events using a single surgical procedure. This approach is a safe and effective method for ameliorating hepatocellular carcinoma.