Purpose: To validate our initial pilot study and confirm sustained safety and tumor response of extended-shelf-life (90)Y glass microspheres. We hypothesized that for the same planned tissue dose, the increase in number of glass microspheres (decayed to the second week of their allowable shelf-life) administered for the same absorbed dose would result in better tumor distribution of the microspheres without causing additional adverse events.
Methods: Between June 2007 and January 2010, 134 patients underwent radioembolization with extended-shelf-life (90)Y glass microspheres; data from 84 new patients were combined with data from our 50-patient pilot study cohort. Baseline and follow-up imaging and laboratory data were obtained 1 and 3 months after therapy and every 3 months thereafter. Clinical and biochemical toxicities were prospectively captured and categorized according to the Common Terminology Criteria. Response in the index lesion was assessed using WHO and EASL guidelines.
Results: The mean delivered radiation dose was 123 Gy to the target liver tissue. The mean increase in number of microspheres with this approach compared to standard (90)Y glass microsphere dosimetry was 103%, corresponding to an increase from 3.84 to 7.78 million microspheres. Clinical toxicities included fatigue (89 patients, 66%), abdominal pain (49 patients, 36.6%), and nausea/vomiting (25 patients, 18.7%). Grade 3/4 bilirubin toxicity was seen in three patients (2%). Two (1%) of the initial 50-patient cohort showed gastroduodenal ulcers; gastroduodenal ulcers were not seen in any of the subsequent 84 patients. According to WHO and EASL guidelines, response rates were 48% and 57%, respectively, and 21% demonstrated a complete EASL response.
Conclusion: This study showed sustained safety and efficacy of extended-shelf-life (90)Y glass microspheres in a larger, 134-patient cohort. The increase in number of microspheres administered theoretically resulted in better tumor distribution of the microspheres without an increase in adverse events.