Dose-response relationships in Y90 resin microsphere radioembolization for patients with hepatocellular carcinoma: insights from a Brazilian cohort

Abstract

Objective: To evaluate the relationship between the absorbed dose and radiological response in patients with hepatocellular carcinoma undergoing resin microsphere radioembolization to enhance treatment precision and potentially adjust protocols for better outcomes.

Methods: This single-center retrospective study was conducted at a quaternary care center in Brazil and comprised 27 patients with 58 target lesions treated between November 2014 and April 2023. The patients' dosimetric profiles were analyzed using advanced imaging software to assess post-treatment clinical and radiological responses. This study explored the correlation between the absorbed doses and tumor objective responses using statistical analyses to confirm the findings.

Results: Higher absorbed doses were significantly associated with improved objective responses in the target lesions. The analysis demonstrated that achieving higher dosimetric thresholds correlated with better clinical outcomes, suggesting that a dose-response relationship is essential to optimize treatment protocols.

Conclusion: These findings emphasize the importance of personalized dosimetry in managing hepatocellular carcinoma using resin microsphere radioembolization. By quantifying the absorbed dose and understanding its impact on tumor response, treatment strategies can be tailored to enhance efficacy and potentially shift palliative treatments toward curative outcomes. This study provides a crucial foundation for dosimetric adjustment and highlights the need for further research in this area, particularly in Brazil.

Graphical abstract

Figure 1. Case of a patient who showed an objective response: A to B) Pretreatment abdominal tomography identifying: Lesion 1: Segment V, near the gallbladder bed, measuring 4.1×3.6cm, hypervascularized with washout (LR-5) and Lesion 2: Segment VII, in contact with the diaphragmatic surface of the liver, measuring 9.5×5.9cm, hypervascularized with washout (LR-5). C) Selective angiography showing a hypervascular lesion in segment V. D) Selective angiography showing a hypervascular lesion in segment VII. E) SPECT-CT following injection of macro-aggregated albumin confirming adequate uptake in the target lesion of segment V, with a hepato-pulmonary shunt of 9.5% and absence of extra-hepatic uptake. The administered activity was 0.8 GBq. F) SPECT-CT after injection of macro-aggregated albumin confirming adequate uptake in the target lesion of segment VII. The administered activity was 2.1 GBq. G) Reconstruction of the Y90 PET in MIM software demonstrating the uptake of the target lesion in segment V, with a strong red color scale for 200Gy and dose reduction in cooler colors. H) Reconstruction of the Y90 PET in MIM software demonstrating the uptake of the target lesion in segment VII, with a strong red color scale for 200Gy and dose reduction in cooler colors. I) Magnetic resonance imaging 90 d post-procedure showing treated hepatic nodules of segment V measuring 2.9cm (average, 3.7cm), predominantly necrotic with thin internal septa and hypervascular enhancement ≤0.3cm thick. J) Magnetic resonance imaging 90 d post-procedure showing the periphery of segment VII measuring 5.5cm (was 7.5cm), with internal hemorrhagic foci, central necrotic area, and solid hypervascular peripheral portion measuring up to 4.8cm (average, 6cm)

Figure 2. Receiver operating characteristics curves differentiating objective response using mean dose and yttrium-90 uptake