Comparison of Dosimetry Models and Dose Thresholds for Predicting Pathologic Response to Yttrium-90 Radioembolization...

Area of Science:

• Hepatobiliary oncology
• Interventional radiology
• Radiation oncology

Background:

• Hepatocellular carcinoma (HCC) is a primary liver malignancy.
• Transarterial radioembolization (TARE) is a treatment modality for HCC.
• Accurate dosimetry is crucial for optimizing TARE outcomes.

Purpose of the Study:

• To evaluate the pathologic response to ablative TARE in HCC.
• To compare the efficacy of single-compartment, mean tumor dose, and voxel-based dosimetry thresholds.
• To identify optimal dose thresholds for predicting complete response.

Main Methods:

• Retrospective, single-center study of patients with HCC treated with glass microsphere TARE.
• Complete response (CR) defined by complete pathologic necrosis (CPN) on explant pathology.
• Comparison of single-compartment, mean tumor, and voxel-based (D95) doses in relation to CR.

Main Results:

• 29 out of 43 patients achieved CR.
• Single-compartment dose ≥ 400 Gy and mean tumor dose ≥ 300-400 Gy were associated with CR (PPV 75-77%).
• Voxel-based D95 ≥ 500 Gy demonstrated the highest PPV for CR (88%) and was significantly associated with response.

Conclusions:

• Increasing single- and dual-compartment dose thresholds beyond 400 Gy did not improve prediction of CR.
• Voxel-based dosimetry (D95 ≥ 500 Gy) is a superior predictor of complete pathologic response in TARE for HCC.
• Dosimetry approach significantly impacts the prediction of treatment efficacy.