Safety and efficacy of repeat Y90 radioembolization to the same hepatic arterial territory

Objective: To study the efficacy and safety of repeat transarterial radioembolization (TARE) to similar hepatic arterial territories. Methods: Between 3/2011 and 4/2019, 26 patients (25 males and 1 Female, Mean Age: 65 yo, SD: 11.7 yo, Range: 18-83.0 yo) received TARE with Y90 glass microspheres to treat recurrent or residual primary disease in similar hepatic arterial lobe or segments. Tumor response was evaluated by imaging using the modified-RECIST criteria. Incidence of RILD and adverse events were categorized by a standardized scale using the Common Terminology Criteria for Adverse Events (CTCAE) v.4.0. Results: Mean cumulative activity after the first treatment was 2.50 GBq (SD:1.04 GBq, Range:0.61-4.93 GBq) and second treatment was 2.27 GBq (SD:1.01 GBq, Range:0.92-5.46 GBq). Mean interval time between initial and repeat treatments was 9.6 months (Range: 1-53 months). Tumor responses were complete, partial, or progression in 73% (n = 19/26), 23% (n = 6/26), and 4% (n = 1/26) in repeat treatment patients, respectively. The incidence of RILD was 0%. Toxicity after first and second treatment was seen in 19% (n = 5/26) & 23% (n = 6/26) patients, respectively, and were all of CTCAE Grade 2. No significant predictors of treatment toxicity for repeat treatment were identified except increased MELD score (p = 0.04). Kaplan-Meier survival analysis in patients with repeat treatment showed a median survival of 15.0 months (95% CI 8.8-21.1 months) and 19.0 months (95% CI 8.1-29.9 months) in patients who only received one treatment with a p value of 0.485. Conclusion: Repeat TARE with glass microspheres was an effective and safe treatment strategy for disease management in patients with residual or recurrent disease to the similar hepatic arterial territories without any major treatment related toxicity. Advances in knowledge: Although safety and efficacy of repeat radioembolism has been studied, no study has focused on repeat treatment to similar hepatic arterial territories. The current study shows that repeat treatment to the same hepatic arterial territory is as safe as single treatment to the same territory.