Clinical and Metabolic Predictors of Response to Transarterial Radioembolization in Primary and Metastatic Liver Tumors: The Role of 18F-FDG PET/CT and Lung Shunt Fraction

Purpose This study aimed to investigate the predictive value of 18F-FDG PET/CT-derived metabolic parameters (SUVmax, MTV, TLG, TLR) and hepatopulmonary shunt fraction (LSF) on the treatment response of transarterial radioembolization (TARE) in patients with primary and metastatic liver tumors. Methods A total of 58 patients who underwent TARE between March 2024 and March 2025 were included. Prior to treatment, all patients underwent 18F-FDG PET/CT and 99mTc-MAA SPECT/CT imaging. PET-based parameters and LSF values were calculated. Treatment response was assessed at 1 and 6 months post-treatment based on mRECIST criteria. Responders were defined as patients with complete or partial response. Statistical analyses included Mann-Whitney U test, Chi-square test, and ROC analysis. Results Of 58 patients, 65.5% (n = 38) were responders. Among PET parameters, lower MTV and TLG values were significantly associated with treatment response (p = 0.004 and p = 0.014, respectively). TLG also demonstrated significance in the HCC subgroup (p = 0.049). SUVmax, TLR, LSF, and administered dose showed no significant association with response. ROC analysis revealed good predictive value for MTV (AUC = 0.703) and TLG (AUC = 0.699), with respective cut-off values of ≤ 61.07 and ≤ 303.99. Demographic and clinical variables such as age, gender, LSF, and dose were not predictive of treatment response. Conclusion Volumetric metabolic parameters, especially TLG, are effective predictors of response to TARE in liver tumors. Incorporating these parameters into clinical evaluation may enhance treatment planning and prognostic estimation. LSF and conventional dose estimation via BSA appear less predictive of localized treatment response.