Personalized Dosimetry with Intensification Using 90Y-Loaded Glass Microsphere Radioembolization Induces Prolonged Overall Survival in Hepatocellular Carcinoma Patients with Portal Vein Thrombosis

The objective of this study was to evaluate the response rate and survival of hepatocellular carcinoma portal vein thrombosis (PVT) patients treated with Y-90-loaded glass microspheres using a personalized dosimetry and intensification concept. Methods: The microspheres were administered to 41 hepatocellular carcinoma PVT patients (main 5 12; lobar/segmental 5 29). Tc-99m-macroaggregated albumin SPECT/CT quantitative analysis was used to calculate the tumor dose (TD), healthy injected liver dose (HILD), and injected liver dose (ILD). Response was evaluated at 3 mo using the criteria of the European Association for the Study of the Liver, with CT follow-up lasting until disease progression or death. Survival was assessed using the Kaplan-Meier method. Results: The mean injected activity was 3.1 +/- 1.5 GBq, and mean ILD was 143 +/- 49 Gy. When a TD threshold of 205 Gy was applied, Tc-99m-macroaggregated albumin SPECT/CT achieved a 100% sensitivity and 90% overall accuracy (0 false-negatives; 4 false-positives) in response prediction. On the basis of TD and HILD values, 37% of patients received an intensification of the treatment (increased injected activity with the aim of achieving a TD >= 205 Gy and HILD < 120 Gy, applying an ILD. 150 Gy). This intensification resulted in a high response rate (85%) without increased liver toxicity of grade 3 or higher (6% vs. 12% in the patients who did not receive treatment intensification; not statistically significant). For the total 41 patients, median overall survival (OS) was 18 mo (95% confidence interval, 11-25 mo). For patients with a TD of less than 205 Gy, median OS was 4.3 mo (3.7-5 mo), versus 18.2 mo (8.5-28.7 mo) for those with a TD of 205 Gy or more (P 5 0.005). Median OS was 20.9 mo for patients with a TD of 205 Gy or more and good PVT targeting (n = 36). OS was 12 mo (3 mo to N) for patients with main PVT, versus 21.5 mo (12-28.7 mo) for those with segmental or lobar PVT (not statistically significant). For the 5 patients with complete portal vein revascularization who underwent lobar hepatectomy, median OS was not reached yet exceeded 24.5 mo and was significantly higher than that of other patients (P = 0.0493). Conclusion: Using a 99mTc-macroaggregated albumin SPECT/CT personalized dosimetry and intensification concept with Y-90-loaded glass microspheres induced prolonged OS for PVT patients as compared with the standard of care (sorafenib), without increasing liver toxicity. Prospective randomized studies are therefore warranted.