Tumor Dose as an Oncologic Predictor of Outcome in Patients with HCC Treated with Resin Y90 Microspheres.

[OBJECTIVE] To evaluate tumor dose (TD) as a predictor of oncological outcomes in patients with hepatocellular carcinoma (HCC) treated with resin Y90 radioembolization (RE), and to evaluate non-tumoral liver dose (NTLD) as a predictor of treatment-related toxicity.

[METHODS] A single-center retrospective review of treatment-naïve HCC patients who underwent resin-based Y90 between 2019 and 2022 was conducted. Baseline demographics, clinical history, and adverse events per CTCAE v5.0 were analyzed. Baseline imaging and post-treatment imaging were also evaluated using Response per Modified Response Evaluation Criteria in Solid Tumors (mRECIST) for tumor response.

[RESULTS] 78 patients (mean age:66.7 years) with 91 tumors underwent Y90-RE, with a median follow-up period of 28.3 months; 23 received lobar Y90-RE, while 55 patients received segmentectomies. Mean TD for the entire cohort was 336.6 ± 291.9 Gy. Mean TD was significantly higher in segmental Y90-RE (424.3 Gy) vs lobar Y90-RE (203.7 Gy) (p < 0.001). At 3 months, 98% of segmentectomy and 72% of lobar patients achieved an objective response (OR), with 90% and 40% achieving complete response (CR), respectively. At 6 months, 97% and 94% of segmentectomy patients achieved OR and CR, compared to 84% and 68% in lobar patients. Mean tumor dose > 250 Gy predicted prolonged overall and progression free survival. A mean NTLD dose of 103 Gy predicted grade 3 + adverse events in lobar treatments.

[CONCLUSION] In patients with HCC treated with resin-based Y90-RE, personalized dosimetry is a key factor in ensuring favorable oncological outcomes. Level of evidence Level 3b, retrospective cohort study.