Signature of survival: a 18F-FDG PET based whole-liver radiomic analysis predicts survival after 90Y-TARE for hepatocellular carcinoma.

PURPOSE: To generate a predictive whole-liver radiomics scoring system for progression-free survival (PFS) and overall survival (OS) in patients undergoing transarterial radioembolization using Yttrium-90 (90Y-TARE) for unresectable hepatocellular carcinoma (uHCC). RESULTS: The generated pPET-RadScores were significantly correlated with survival for PFS (median of 11.4 mo [95% confidence interval CI: 6.3-16.5 mo] in low-risk group [PFS-pPET-RadScore < 0.09] vs. 4.0 mo [95% CI: 2.3-5.7 mo] in high-risk group [PFS-pPET-RadScore > 0.09]; P = 0.0004) and OS (median of 20.3 mo [95% CI: 5.7-35 mo] in low-risk group [OS-pPET-RadScore < 0.11] vs. 7.7 mo [95% CI: 6.0-9.5 mo] in high-risk group [OS-pPET-RadScore > 0.11]; P = 0.007). The multivariate analysis confirmed PFS-pPET-RadScore (P = 0.006) and OS-pPET-RadScore (P = 0.001) as independent negative predictors. CONCLUSION: Pretreatment 18F-FDG PET whole-liver radiomics signature appears as an independent negative predictor for PFS and OS in patients undergoing 90Y-TARE for uHCC. METHODS: Pretreatment 18F-FDG PET of 47 consecutive patients undergoing 90Y-TARE for uHCC (31 resin spheres, 16 glass spheres) were retrospectively analyzed. For each patient, based on PET radiomics signature from whole-liver semi-automatic segmentation, PFS and OS predictive PET-radiomics scores (pPET-RadScores) were obtained using LASSO Cox regression. Using X-tile software, the optimal score to predict PFS (PFS-pPET-RadScore) and OS (OS-pPET-RadScore) served as cutoff to separate high and low-risk patients. Survival curves were estimated using the Kaplan-Meier method. The prognostic value of PFS and OS-pPET-RadScore, Barcelona-Clinic Liver Cancer staging system and serum alpha-fetoprotein level was analyzed to predict PFS and OS in multivariate analysis.

18F-FDG PET/CT predicts survival after 90Y transarterial radioembolization in unresectable hepatocellular carcinoma.

PURPOSE: To compare the value of pretreatment functional and morphological imaging parameters for predicting survival in patients undergoing transarterial radioembolization using yttrium-90 (90Y-TARE) for unresectable hepatocellular carcinoma (uHCC). METHODS: We analysed data from 48 patients in our prospective database undergoing 90Y-TARE treatment for uHCC (31 resin, 17 glass). All patients underwent 18F-FDG PET/CT and morphological imaging (CT and MRI scans) as part of a pretherapeutic work-up. Patients did not receive any treatment between these imaging procedures and 90Y-TARE. Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS) were used to assess the prognostic value of 18F-FDG PET/CT metabolic parameters, including SUVmax, tumour-to-liver (T/L) uptake ratio and SUVmean of healthy liver, and morphological data, including number and size of lesions, portal-venous infiltration (PVI). Relevant prognostic factors for HCC including Child-Pugh class, Barcelona Clinic Liver Cancer (BCLC) stage, tumour size, PVI and serum AFP level were compared with metabolic parameters in univariate and multivariate analyses. RESULTS: The median follow-up in living patients was 16.2 months (range 11.4-50.1 months). Relapse occurred in 34 patients (70.8%) at a median of 7.4 months (range 1.4-27.9 months) after 90Y-TARE, and relapse occurred in 24 of 34 patients (70.8%) who died from their disease at a median of 8.1 months (range 2.2-35.2 months). Significant prognostic markers for PFS were the mean and median lesion SUVmax (both P = 0.01; median PFS 10.2 vs. 7.4 months), and significant prognostic markers for OS were the first quarter (Q1) cut-off values for lesion SUVmax and T/L uptake ratio (both P = 0.02; median OS 30.9 vs. 9 months). The multivariate analysis confirmed that lesion SUVmax and T/L uptake ratio were independent negative predictors of PFS (hazard ratio, HR, 2.7, 95% CI 1.2-6.1, P = 0.02, for mean SUVmax; HR 2.6, 95% CI 1.1-5.9, P = 0.02, for median SUVmax:) and OS (HR 3.2, 95% CI 1-10.9, P = 0.04 for Q1 SUVmax; HR 3.7, 95% CI 1.1-12.2, P = 0.03, for Q1 T/L uptake ratio), respectively, when testing with either the BCLC staging system or serum AFP level. CONCLUSION: Lesion SUVmax and T/L uptake ratio as assessed by 18F-FDG PET/CT, but not morphological imaging, were predictive markers of survival in patients undergoing 90Y-TARE for uHCC.

Resin Versus Glass Microspheres for 90Y Transarterial Radioembolization: Comparing Survival in Unresectable Hepatocellular Carcinoma Using Pretreatment Partition Model Dosimetry.

The aim of this study was to compare survival of patients treated for unresectable hepatocellular carcinoma (uHCC) with 90Y transarterial radioembolization (TARE) using pretreatment partition model dosimetry (PMD). Methods: We performed a retrospective analysis of prospectively collected data on 77 patients consecutively treated (mean age ± SD, 66.4 ± 12.2 y) for uHCC (36 uninodular, 5 multinodular, 36 diffuse) with 90Y TARE (41 resin, 36 glass) using pretreatment PMD. Study endpoints were progression-free survival (PFS) and overall survival (OS) assessed by Kaplan-Meier estimates. Several variables including Barcelona Clinic Liver Cancer (BCLC) staging system, tumor size, and serum α-fetoprotein (AFP) level were investigated using Cox proportional hazards regression. Results: The characteristics of 2 groups were comparable with regard to demographic data, comorbidities, Child-Pugh score, BCLC, serum AFP level, and 90Y global administered activity. The median follow-up time was 7.7 mo (range, 0.4-50.1 mo). Relapse occurred in 44 patients (57%) at a median of 6 mo (range, 0.4-27.9 mo) after 90Y TARE, and 41 patients (53%) died from tumor progression. Comparison between resin and glass microspheres revealed higher but not statistically significantly PFS and OS rates in the 90Y resin group than the 90Y glass group (resin PFS 6.1 mo [95% confidence interval CI, 4.7-7.4] and glass PFS 5 mo [95% CI, 0.9-9.2], P = 0.53; resin OS 7.7 mo [95% CI, 7.2-8.2] and glass OS 7 mo [95% CI 1.6-12.4], P = 0.77). No significant survival difference between both types of 90Y microspheres was observed in any subgroups of patients with early/intermediate or advanced BCLC stages. Among the variables investigated, Cox analyses showed that only in the glass group, the BCLC staging system and the serum AFP level were associated with PFS (P = 0.04) and OS (P = 0.04). Tumor size was a prognostic factor without significant influence on PFS and OS after 90Y TARE. Conclusion: Comparison between resin and glass microspheres revealed no significant survival difference in patients treated for uHCC with 90Y TARE using pretreatment PMD. Further, larger prospective studies are warranted to confirm these findings.

Partition Model-Based 99mTc-MAA SPECT/CT Predictive Dosimetry Compared with 90Y TOF PET/CT Posttreatment Dosimetry in Radioembolization of Hepatocellular Carcinoma: A Quantitative Agreement Comparison.

90Y-microsphere selective internal radiation therapy (SIRT) is a valuable treatment in unresectable hepatocellular carcinoma (HCC). Partition-model predictive dosimetry relies on differential tumor-to-nontumor perfusion evaluated on pretreatment 99mTc-macroaggregated albumin (MAA) SPECT/CT. The aim of this study was to evaluate agreement between the predictive dosimetry of 99mTc-MAA SPECT/CT and posttreatment dosimetry based on 90Y time-of-flight (TOF) PET/CT. METHODS: We compared the 99mTc-MAA SPECT/CT results for 27 treatment sessions (25 HCC patients, 41 tumors) with 90Y SIRT (7 glass spheres, 20 resin spheres) and the posttreatment 90Y TOF PET/CT results. Three-dimensional voxelized dose maps were computed from the 99mTc-MAA SPECT/CT and 90Y TOF PET/CT data. Mean absorbed dose ([Formula: see text]) was evaluated to compute the predicted-to-actual dose ratio ([Formula: see text]) in tumor volumes (TVs) and nontumor volumes (NTVs) for glass and resin spheres. The Lin concordance ([Formula: see text]) was used to measure accuracy ([Formula: see text]) and precision (ρ). RESULTS: Administered activity ranged from 0.8 to 1.9 GBq for glass spheres and from 0.6 to 3.4 GBq for resin spheres, and the respective TVs ranged from 2 to 125 mL and from 6 to 1,828 mL. The mean dose [Formula: see text] was 240 Gy for glass and 122 Gy for resin in TVs and 72 Gy for glass and 47 Gy for resin in NTVs. [Formula: see text] was 1.46 ± 0.58 (0.65-2.53) for glass and 1.16 ± 0.41 (0.54-2.54) for resin, and the respective values for [Formula: see text] were 0.88 ± 0.15 (0.56-1.00) and 0.86 ± 0.2 (0.58-1.35). DR variability was substantially lower in NTVs than in TVs. The Lin concordance between [Formula: see text] and [Formula: see text] (resin) was significantly better for tumors larger than 150 mL than for tumors 150 mL or smaller ([Formula: see text] = 0.93 and [Formula: see text] = 0.95 vs. [Formula: see text] = 0.57 and [Formula: see text] = 0.93; P < 0.05). CONCLUSION: In 90Y radioembolization of HCC, predictive dosimetry based on 99mTc-MAA SPECT/CT provided good estimates of absorbed doses calculated from posttreatment 90Y TOF PET/CT for tumor and nontumor tissues. The low variability of [Formula: see text] demonstrates that pretreatment dosimetry is particularly suitable for minimizing radiation-induced hepatotoxicity.