Hypoxia is a known cause of resistance to radiotherapy and chemotherapy. Although there are multiple studies in external radiation therapies based on hypoxia PET, the effect of hypoxia in radioembolization is largely unknown. Here we present 2 cases of hepatocellular carcinoma patients from a prospective study with different lesion characteristics on pretreatment ¹⁸F-FMISO PET and varying responses on ¹⁸F-FDG PET.

Purpose: The aim of this study was to investigate the differences between voxel-based dosimetry and the mean absorbed doses calculated with pre-treatment Tc-99 m-MAA SPECT/CT and post-treatment Y-90 PET/MR images. We also sought to present a detailed comparison of dose-volume histograms (DVHs) calculated from pre- and post-treatment imaging. Methods: A total of 47 treatments and 41 patients were included in the analysis as six of the treatments were retreatments of the six patients. Multicompartment and voxel-based dosimetry were performed with pre-treatment Tc-99m-MAA SPECT/CT and Y-90 PET/MRI. Correlation coefficients between the two imaging methods for the mean absorbed dose of tumor, whole liver normal tissue, perfused normal tissue, T/N ratio and tumor D10, D50 and D90 values were calculated. Additionally, differences between these values were also evaluated with Bland–Altman plots. Results: Pre-treatment Tc-99m-MAA SPECT/CT accurately predicted the dose values for healthy liver parenchyma calculated with Y-90 PET/MRI but showed lower accuracy in predicting T/N ratio and tumor doses. There were significant variations in tumor-absorbed doses for both glass and resin microspheres. Additionally, D90 values were higher when calculated with SPECT/CT than with PET/MRI, whereas D10 values were higher in PET/MRI compared to SPECT/CT. Conclusion: The findings in our study suggest that Tc-99m-MAA SPECT/CT had higher accuracy in predicting the dose to the healthy liver parenchyma compared to the tumor, maintaining its importance in treatment planning.

Purpose: Previous studies have reported that blood-based inflammatory markers are associated with prognosis in patients with various solid tumors, including colorectal cancer (CRC). The pan-immune inflammation value (PIV) is a novel prognostic biomarker based on blood count. Here, we aimed to study the association between PIV and survival following transarterial radioembolization (TARE) in patients with liver-dominant metastatic colorectal cancer (CLM). Methods: A total of 49 patients with CLM who underwent TARE at the Ankara University Department of Medical Oncology were retrospectively analyzed. The relationship between clinical and laboratory parameters with post-TARE overall survival (OS) was analyzed by multivariate analyses. Results: The median age was 60 years and 71.4% of patients had received at least two lines of chemotherapy. The objective response rate (ORR) was 59.1% following TARE. Patients with hepatic response after TARE treatment demonstrated significantly longer survival compared to non-responders (p: 0.033). The optimal PIV threshold value was calculated as 629 in ROC analyses. This PIV value had 81% sensitivity and 80% specificity for OS prediction (AUC 0.86; 95% CI: 0.75–0.98, p = 0.008). Patients with elevated PIV > 629 had significantly shorter OS (p = 0.002). In the multivariate analysis, adjusted for ECOG PS, TARE response, presence of extrahepatic disease, number of chemotherapy lines, CEA levels and post-TARE NLR and PIV, only low PIV level was associated with longer OS (>629 vs. ≤629; HR: 4.87; 95% CI: 1.32–17.92; p = 0.017). Conclusions: PIV, a blood-based inflammatory score, may reflect the host’s immune response following TARE and serve as a novel predictor of survival.