Chemotherapy with or without selective internal radiation therapy for intrahepatic cholangiocarcinoma: Data from clinical trials.

BACKGOUND AND AIMS: In advanced, liver-only intrahepatic cholangiocarcinoma (iCCA), selective internal radiation therapy (SIRT) has been suggested as promising in nonrandomized studies. We aimed to compare data from patients with advanced, liver-only iCCA treated in the first line in clinical trials with either chemotherapy alone or the combination with SIRT. APPROACH AND RESULTS: We collected individual patients' data from the ABC-01, ABC-02, ABC-03, BINGO, AMEBICA, and MISPHEC prospective trials. Data from patients with liver-only iCCA treated in chemotherapy-only arms of the first 5 trials were compared with data from patients treated with SIRT and chemotherapy in MISPHEC. Emulated target trial paradigm and Inverse Probability of Treatment Weighting (IPTW methods) using the propensity score were used to minimize biases. We compared 41 patients treated with the combination with 73 patients treated with chemotherapy alone, the main analysis being in 43 patients treated with cisplatin-gemcitabine or gemcitabine-oxaliplatin. After weighting, overall survival was significantly higher in patients treated with SIRT: median 21.7 months (95% CI: 14.1; not reached) versus 15.9 months(95% CI: 9.8; 18.9), HR = 0.59 (95% CI: 0.34; 0.99), p = 0.049. Progression-free survival was significantly improved: median 14.3 months (95% CI: 7.8; not reached) versus 8.4 months (95% CI: 5.9; 12.1), HR = 0.52 (95% CI: 0.31; 0.89), p < 0.001. Results were confirmed in most sensitivity analyses. CONCLUSIONS: This analysis derived from prospective clinical trials suggests that SIRT combined with chemotherapy might improve outcomes over chemotherapy alone in patients with advanced, liver-only iCCA. Randomized controlled evidence is needed to confirm these findings.

Optimal patient selection for yttrium-90 glass plus chemotherapy in the treatment of colorectal liver metastases: additional quality of life, efficacy, and safety analyses from the EPOCH study.

BACKGROUND: Evaluating transarterial radioembolization (TARE) in patients with metastatic colorectal carcinoma of the liver who have progressed on first-line chemotherapy (EPOCH) demonstrated superior outcomes using yttrium-90 glass microspheres plus chemotherapy (TARE/Chemo) vs chemotherapy (Chemo) to treat colorectal liver metastases. Additional exploratory analyses were undertaken to assess the impact of TARE/Chemo on efficacy, safety, time to subsequent therapy, time to deterioration in quality of life (QoL), and identify criteria for improved patient selection. METHODS: Time to deterioration in QoL was analyzed for the primary study population. Subsequently, a post hoc analysis was undertaken to identify subgroups for which time to deterioration in QoL was improved with TARE/Chemo vs Chemo. Progression-free survival (PFS), hepatic (h)PFS, time to subsequent therapy, and safety outcomes were compared between treatments. RESULTS: The primary population showed no significant difference in time to deterioration in QoL between treatment arms; however, significance was seen in 2 identified subgroups, namely: Subgroup A (N = 303) which excluded patients with both Eastern Cooperative Oncology Group (ECOG) 1 and baseline CEA ≥ 35 ng/mL from both treatment arms; subgroup B (N = 168) additionally excluded patients with KRAS (Kirsten rat sarcoma) mutation. In subgroup A, TARE/Chemo patients (N = 143) demonstrated superior outcomes vs Chemo (N = 160): PFS (9.4 vs. 7.6 months, hazard ratio (HR): 0.64; 1-sided P = .0020), hPFS (10.8 vs. 7.6 months, HR: 0.53; 1-sided P < .0001), time to deterioration in QoL (5.7 vs. 3.9 months, HR: 0.65; 1-sided P = .0063), and time to subsequent therapy (21.2 vs. 10.5 months, HR: 0.52; 1-sided P < .0001). Subgroup B patients showed similar but larger significant differences between treatment arms. Median PFS, hPFS, and time to deterioration in QoL were numerically greater for TARE/Chemo in both subgroups vs the primary population, with the greatest magnitude of difference in subgroup B. Both subgroups exhibited higher percentage of CEA responders and improved ORR with TARE/Chemo vs chemo alone. Safety (reported as event rate/100 patient-years) was higher with Chemo in all populations. Additional efficacy analyses in the primary population are also reported. CONCLUSIONS: Careful patient selection, including consideration of the prognostic factors ECOG, baseline CEA, and KRAS status, sets outcome expectations in patients with colorectal liver metastases suitable for TARE/Chemo as second-line treatment (Trial Registry Number: NCT01483027).

Utility of pre-procedural [99mTc]TcMAA SPECT/CT Multicompartment Dosimetry for Treatment Planning of 90Y Glass microspheres in patients with Hepatocellular Carcinoma: comparison of anatomic versus [99mTc]TcMAA-based Segmentation.

PURPOSE: Pre-treatment [99mTc]TcMAA-based radioembolization treatment planning using multicompartment dosimetry involves the definition of the tumor and normal tissue compartments and calculation of the prescribed absorbed doses. The aim was to compare the real-world utility of anatomic and [99mTc]TcMAA-based segmentation of tumor and normal tissue compartments. MATERIALS AND METHODS: Included patients had HCC treated by glass [90Y]yttrium microspheres, ≥ 1 tumor, ≥ 3 cm diameter and [99mTc]TcMAA SPECT/CT imaging before treatment. Segmentation was performed retrospectively using dedicated dosimetry software: (1) anatomic (diagnostic CT/MRI-based), and (2) [99mTc]TcMAA threshold-based (i.e., using an activity-isocontour threshold). CT/MRI was co-registered with [99mTc]TcMAA SPECT/CT. Logistic regression and Cox regression, respectively, were used to evaluate relationships between total perfused tumor absorbed dose (TAD) and objective response rate (ORR) and overall survival (OS). In a subset-analysis pre- and post-treatment dosimetry were compared using Bland-Altman analysis and Pearson's correlation coefficient. RESULTS: A total of 209 patients were enrolled. Total perfused tumor and normal tissue volumes were larger when using anatomic versus [99mTc]TcMAA threshold segmentation, resulting in lower absorbed doses. mRECIST ORR was higher with increasing total perfused TAD (odds ratio per 100 Gy TAD increase was 1.22 (95% CI: 1.01-1.49; p = 0.044) for anatomic and 1.19 (95% CI: 1.04-1.37; p = 0.012) for [99mTc]TcMAA threshold segmentation. Higher total perfused TAD was associated with improved OS (hazard ratio per 100 Gy TAD increase was 0.826 (95% CI: 0.714-0.954; p = 0.009) and 0.847 (95% CI: 0.765-0.936; p = 0.001) for anatomic and [99mTc]TcMAA threshold segmentation, respectively). For pre- vs. post-treatment dosimetry comparison, the average bias for total perfused TAD was + 11.5 Gy (95% limits of agreement: -227.0 to 250.0) with a strong positive correlation (Pearson's correlation coefficient = 0.80). CONCLUSION: Real-world data support [99mTc]TcMAA imaging to estimate absorbed doses prior to treatment of HCC with glass [90Y]yttrium microspheres. Both anatomic and [99mTc]TcMAA threshold methods were suitable for treatment planning. TRIAL REGISTRATION NUMBER: NCT03295006.

Resection Postradioembolization in Patients With Single Large Hepatocellular Carcinoma.

OBJECTIVE: The aim of this study was to evaluate the efficacy of yttrium-90 transarterial radioembolization (TARE) to convert to resection initially unresectable, single, large (≥5 cm) hepatocellular carcinoma (HCC). BACKGROUND: TARE can downsize cholangiocarcinoma to resection but its role in HCC resectability remains debatable. METHODS: All consecutive patients with a single large HCC treated between 2015 and 2020 in a single tertiary center were reviewed. When indicated, patients were either readily resected (upfront surgery) or underwent TARE. TARE patients were converted to resection (TARE surgery) or not (TARE-only). To further assess the effect of TARE on the long-term and short-term outcomes, a propensity score matching analysis was performed. RESULTS: Among 216 patients, 144 (66.7%) underwent upfront surgery. Among 72 TARE patients, 20 (27.7%) were converted to resection. TARE-surgery patients received a higher mean yttrium-90 dose that the 52 remaining TARE-only patients (211.89±107.98 vs 128.7±36.52 Gy, P <0.001). Postoperative outcomes between upfront-surgery and TARE-surgery patients were similar. In the unmatched population, overall survival at 1, 3, and 5 years was similar between upfront-surgery and TARE-surgery patients (83.0%, 60.0%, 47% vs 94.0%, 86.0%, 55.0%, P =0.43) and compared favorably with TARE-only patients (61.0%, 16.0% and 9.0%, P <0.0001). After propensity score matching, TARE-surgery patients had significantly better overall survival than upfront-surgery patients ( P =0.021), while disease-free survival was similar ( P =0.29). CONCLUSION: TARE may be a useful downstaging treatment for unresectable localized single large HCC providing comparable short-term and long-term outcomes with readily resectable tumors.

Direct comparison and reproducibility of two segmentation methods for multicompartment dosimetry: round robin study on radioembolization treatment planning in hepatocellular carcinoma.

PURPOSE: Investigate reproducibility of two segmentation methods for multicompartment dosimetry, including normal tissue absorbed dose (NTAD) and tumour absorbed dose (TAD), in hepatocellular carcinoma patients treated with yttrium-90 (90Y) glass microspheres. METHODS: TARGET was a retrospective investigation in 209 patients with < 10 tumours per lobe and at least one tumour ≥ 3 cm ± portal vein thrombosis. Dosimetry was compared using two distinct segmentation methods: anatomic (CT/MRI-based) and count threshold-based on pre-procedural 99mTc-MAA SPECT. In a round robin substudy in 20 patients with ≤ 5 unilobar tumours, the inter-observer reproducibility of eight reviewers was evaluated by computing reproducibility coefficient (RDC) of volume and absorbed dose for whole liver, whole liver normal tissue, perfused normal tissue, perfused liver, total perfused tumour, and target lesion. Intra-observer reproducibility was based on second assessments in 10 patients ≥ 2 weeks later. RESULTS: 99mTc-MAA segmentation calculated higher absorbed doses compared to anatomic segmentation (n = 209), 43.9% higher for TAD (95% limits of agreement [LoA]: - 49.0%, 306.2%) and 21.3% for NTAD (95% LoA: - 67.6%, 354.0%). For the round robin substudy (n = 20), inter-observer reproducibility was better for anatomic (RDC range: 1.17 to 3.53) than 99mTc-MAA SPECT segmentation (1.29 to 7.00) and similar between anatomic imaging modalities (CT: 1.09 to 3.56; MRI: 1.24 to 3.50). Inter-observer reproducibility was better for larger volumes. Perfused normal tissue volume RDC was 1.95 by anatomic and 3.19 by 99mTc-MAA SPECT, with corresponding absorbed dose RDC 1.46 and 1.75. Total perfused tumour volume RDC was higher, 2.92 for anatomic and 7.0 by 99mTc-MAA SPECT with corresponding absorbed dose RDC of 1.84 and 2.78. Intra-observer variability was lower for perfused NTAD (range: 14.3 to 19.7 Gy) than total perfused TAD (range: 42.8 to 121.4 Gy). CONCLUSION: Anatomic segmentation-based dosimetry, versus 99mTc-MAA segmentation, results in lower absorbed doses with superior reproducibility. Higher volume compartments, such as normal tissue versus tumour, exhibit improved reproducibility. TRIAL REGISTRATION: NCT03295006.

Clinical, dosimetric, and reporting considerations for Y-90 glass microspheres in hepatocellular carcinoma: updated 2022 recommendations from an international multidisciplinary working group.

PURPOSE: In light of recently published clinical reports and trials, the TheraSphere Global Dosimetry Steering Committee (DSC) reconvened to review new data and to update previously published clinical and dosimetric recommendations for the treatment of hepatocellular carcinoma (HCC). METHODS: The TheraSphere Global DSC is comprised of health care providers across multiple disciplines involved in the treatment of HCC with yttrium-90 (Y-90) glass microsphere-based transarterial radioembolization (TARE). Literature published between January 2019 and September 2021 was reviewed, discussed, and adjudicated by the Delphi method. Recommendations included in this updated document incorporate both the results of the literature review and the expert opinion and experience of members of the committee. RESULTS: Committee discussion and consensus led to the expansion of recommendations to apply to five common clinical scenarios in patients with HCC to support more individualized efficacious treatment with Y-90 glass microspheres. Existing clinical scenarios were updated to reflect recent developments in dosimetry approaches and broader treatment paradigms evolving for patients presenting with HCC. CONCLUSION: Updated consensus recommendations are provided to guide clinical and dosimetric approaches for the use of Y-90 glass microsphere TARE in HCC, accounting for disease presentation, tumor biology, and treatment intent.

Defining textbook outcome for selective internal radiation therapy of hepatocellular carcinoma: an international expert study.

BACKGROUND: A textbook outcome (TO) is a composite indicator covering the entire intervention process in order to reflect the "ideal" intervention and be a surrogate for patient important outcomes. Selective internal radiation therapy (SIRT) is a complex multidisciplinary and multistep intervention facing the challenge of standardization. This expert opinion-based study aimed to define a TO for SIRT of hepatocellular carcinoma. METHODS: This study involved two steps: (1) the steering committee (4 interventional radiologists) first developed an extensive list of possible relevant items reflecting an optimal SIRT intervention based on a literature review and (2) then conducted an international and multidisciplinary survey which resulted in the final TO. This survey was online, from February to July 2021, and consisted three consecutive rounds with predefined settings. Experts were identified by contacting senior authors of randomized trials, large observational studies, or studies on quality improvement in SIRT. This study was strictly academic. RESULTS: A total of 50 items were included in the first round of the survey. A total of 29/40 experts (73%) responded, including 23 interventional radiologists (79%), three nuclear medicine physicians (10%), two hepatologists, and one oncologist, from 11 countries spanning three continents. The final TO consisted 11 parameters across six domains ("pre-intervention workup," "tumor targeting and dosimetry," "intervention," "post-90Y imaging," "length of hospital stay," and "complications"). Of these, all but one were applied in the institutions of > 80% of experts. CONCLUSIONS: This multidimensional indicator is a comprehensive standardization tool, suitable for routine care, clinical round, and research.

A global evaluation of advanced dosimetry in transarterial radioembolization of hepatocellular carcinoma with Yttrium-90: the TARGET study.

PURPOSE: To investigate the relationships between tumor absorbed dose (TAD) or normal tissue absorbed dose (NTAD) and clinical outcomes in hepatocellular carcinoma (HCC) treated with yttrium-90 glass microspheres. METHODS: TARGET was a retrospective investigation in 13 centers across eight countries. Key inclusion criteria: liver-dominant HCC with or without portal vein thrombosis, < 10 tumors per lobe (at least one ≥ 3 cm), Child-Pugh stage A/B7, BCLC stages A-C, and no prior intra-arterial treatment. Multi-compartment pre-treatment dosimetry was performed retrospectively. Primary endpoint was the relationship between ≥ grade 3 hyperbilirubinemia (such that > 15% of patients experienced an event) without disease progression and NTAD. Secondary endpoints included relationships between (1) objective response (OR) and TAD, (2) overall survival (OS) and TAD, and (3) alpha fetoprotein (AFP) and TAD. RESULTS: No relationship was found between NTAD and ≥ grade 3 hyperbilirubinemia, which occurred in 4.8% of the 209 patients. The mRECIST OR rate over all lesions was 61.7%; for the target (largest) lesion, 70.8%. Responders and non-responders had geometric mean total perfused TADs of 225.5 Gy and 188.3 Gy (p = 0.048). Probability of OR was higher with increasing TAD (p = 0.044). Higher TAD was associated with longer OS (HR per 100 Gy increase = 0.83, 95% CI: 0.71-0.95; p = 0.009). Increased TAD was associated with higher probability of AFP response (p = 0.046 for baseline AFP ≥ 200 ng/mL). CONCLUSION: Real-world data confirmed a significant association between TAD and OR, TAD and OS, and TAD and AFP response. No association was found between ≥ grade 3 hyperbilirubinemia and NTAD. TRIAL REGISTRATION NUMBER: NCT03295006.

Relationship of Tumor Radiation-absorbed Dose to Survival and Response in Hepatocellular Carcinoma Treated with Transarterial Radioembolization with 90Y in the SARAH Study.

Background Little is known about factors that influence the efficacy of transarterial radioembolization (TARE). Purpose To determine the relationship between tumor radiation-absorbed dose and survival and tumor response in locally advanced inoperable hepatocellular carcinoma treated with TARE. Materials and Methods This was a secondary analysis of prospectively acquired data (between December 2011 and March 2015) from participants who received TARE in the Sorafenib versus Radioembolization in Advanced Hepatocellular Carcinoma (SARAH) trial (ClinicalTrials.gov identifier: NCT01482442). Tumor-absorbed dose was computed using technetium 99m (99mTc) macroaggregated human albumin (MAA) SPECT/CT. Visual agreement among CT, 99mTc-MAA SPECT/CT, and yttrium 90 (90Y) SPECT/CT or PET/CT was scored as optimal, suboptimal, or not optimal. Overall survival (OS) and tumor response at 6-month follow-up CT (Response Evaluation Criteria in Solid Tumors, version 1.1) were assessed. OS was evaluated using Kaplan-Meier tests. A propensity score comparing participants receiving a tumor dose greater than or equal to 100 Gy (best cut-off according to the receiver operating characteristic curve and median tumor radiation-absorbed dose values in the study groups) with those receiving sorafenib was calculated. Results One hundred twenty-one participants (median age, 67 years; interquartile range [IQR]: 61-73 years; 110 men) were evaluated in the dose-survival group, and 109 (median age, 66 years; IQR: 61-71 years; 100 men) were evaluated in the dose-tumor response group. In the dose-survival group, median OS was 9.3 months (95% confidence interval [CI]: 6.7 months, 10.7 months), and median tumor radiation-absorbed dose was 112 Gy (IQR: 68-220 Gy). Participants who received at least 100 Gy (n = 67) had longer survival than those who received less than 100 Gy (median, 14.1 months [95% CI: 9.6 months, 18.6 months] vs 6.1 months [95% CI: 4.9 months, 6.8 months], respectively; P < .001), and those with optimal agreement (n = 24) had the longest median OS (24.9 months; 95% CI: 9.6 months, 33.9 months). In the dose-tumor response group, tumor radiation-absorbed dose was higher in participants with disease control versus those with progressive disease (median, 121 Gy [IQR: 86-190 Gy] vs 85 Gy [IQR: 58-164 Gy]; P = .02). The highest disease control rate was observed in 31 of 40 participants (78%) with a tumor radiation-absorbed dose greater than or equal to 100 Gy and optimal agreement. Conclusion Higher tumor radiation-absorbed dose computed at technetium 99m macroaggregated human albumin SPECT/CT was associated with better overall survival and disease control in hepatocellular carcinoma treated with transarterial radioembolization with yttrium 90 in the Sorafenib versus Radioembolization in Advanced Hepatocellular Carcinoma trial. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Sofocleous and Kamarinos in this issue.

Downstaging with Radioembolization or Chemotherapy for Initially Unresectable Intrahepatic Cholangiocarcinoma.

OBJECTIVE: The aim of this retrospective study was to compare the outcomes of patients resected for intrahepatic cholangiocarcinoma (ICC) with upfront surgery or after downstaging treatment. METHODS: All consecutive patients with ICC between January 1997 and November 2017 were included in a single-center database and retrospectively reviewed. Patients were divided into two groups: upfront resection or resection after downstaging using either chemotherapy alone or selective internal radiation therapy (SIRT) combined with chemotherapy. Survival rates of patients who underwent upfront surgery for ICC were compared with those of patients who underwent surgery after downstaging therapy. RESULTS: A total of 169 patients resected for ICC were included: 137 underwent upfront surgery and 32 received downstaging treatment because their tumor was initially unresectable (13 received chemotherapy, 19 received SIRT). Median OS was not different between the two groups: 32.3 months [95% confidence interval (CI) 23.9-40.7] with primary surgery versus 45.9 months (95% CI 32.3-59.4) with downstaging treatment (p = 0.54, log-rank test). In a multivariable Cox regression model, downstaging treatment was not associated with a better or worse prognosis; however, delivery of SIRT as a downstaging treatment was associated with a significant benefit in multivariable analysis (hazard ratio 0.34, 95% CI 0.14-0.84; p = 0.019). CONCLUSIONS: Overall survival of patients resected after downstaging treatment was not different compared with the OS of patients resected upfront. Patients should therefore again be discussed with the surgeon following medical treatment. SIRT may be an efficient neoadjuvant therapy in patients with resectable ICC, in order to improve surgical results.

Preliminary results of the Phase 1 Lip-Re I clinical trial: biodistribution and dosimetry assessments in hepatocellular carcinoma patients treated with 188Re-SSS Lipiodol radioembolization.

PURPOSE: This study sought to provide preliminary results on the biodistribution and dosimetry following intra-arterial liver injection of 188Re-SSS Lipiodol on hepatocellular carcinoma patients included in the Phase I Lip-Re 1 study. METHODS: Results of the first six patients included are reported. Analysis of the 188Re-SSS Lipiodol biodistribution was based on planar scintigraphic and tomoscintigraphic (SPECT) studies performed at 1, 6, 24, 48, and 72 h post-administration. Quantification in blood, urine, and stool samples was performed. Determination of the tumour to non-tumour uptake ratio (T/NT) was calculated. Absorbed doses to target organs and tumours were evaluated using the MIRD formalism. RESULTS: The mean injected activity of 188Re-SSS Lipiodol was 1645 ± 361 MBq. Uptakes were seen in the liver (tumour and healthy liver) and the lungs only. All these uptakes were stable over time. A mean 1.4 ± 0.7% of 188Re-SSS Lipiodol administered was detected in serum samples at 6 h, declining rapidly thereafter. On average, 1.5 ± 1.6% of administered activity was eliminated in urine and feces over 72 h. Overall, 90.7 ± 1.6% of detected activity on SPECT studies was found in the liver (74.9 ± 1.8% in tumours and 19.1 ± 1.7% in the healthy liver) and 9.3 ± 1.6% in the lungs (5.7 ± 1.1% in right and 3.7 ± 0.5% in left lungs). Mean doses absorbed were 7.9 ± 3.7Gy to the whole liver, 42.7 ± 34.0Gy to the tumours, 10.2 ± 3.7Gy to the healthy liver, and 1.5 ± 1.2Gy to the lungs. Four patients had stable disease on CT scans at 2 months. The first patient with rapidly progressive disease died at 1 month, most probably of massive tumour progression. Due to this early death and using a conservative approach, the trial independent evaluation committee decided to consider this event as a treatment-related toxicity. CONCLUSION: 188Re-SSS Lipiodol has a favorable biodistribution profile concerning radioembolization, with the highest in-vivo stability among all radiolabeled Lipiodol compounds reported to date. These preliminary results must be further confirmed while completing this Phase I Lip Re1 study.

Yttrium-90 glass microspheres radioembolization (RE) for biliary tract cancer: a large single-center experience.

PURPOSE: Radioembolization (RE) is a promising treatment option for biliary tract cancers (BTC). We report here the largest series to date using this treatment modality. METHODS: We retrospectively studied data from 64 patients treated outside prospective clinical trial at our institution. We studied baseline characteristics as potential prognostic factors. We studied dose delivered to the tumor as predictive factors of outcomes in patients not receiving concomitant chemotherapy. RESULTS: The Progression-Free Survival and Overall Survival (OS) were 7.6 months [95% Confidence Interval (CI): 4.6-10.6] and 16.4 months [95% CI: 7.8-25.0] in the whole cohort. The factors independently associated with OS in multivariable analysis were the primary localization of ICC (HR = 0.27, 95% CI: 0.11-0.68, p = 0.005) and a PS > 0 (HR = 2.21, 95% CI: 1.11-4.38, p = 0.024). During follow-up, 12 patients (19%) underwent surgery following downstaging, with a median OS of 51.9 months. In patients not treated with concomitant chemotherapy (n = 31), OS was significantly higher in patients with a dose delivered to the tumor 260Gy or higher than in patients with a dose delivered to the tumor lower than 260Gy (median 28.2 vs 11.4 months, log-rank p = 0.019). CONCLUSION: Our results confirm that RE is a promising treatment modality in BTC. A high proportion of patients could be downstaged to surgery, with promising long-term survival. Dose delivered to the tumor correlated with clinical outcomes when chemotherapy was not used concomitantly.

Clinical and dosimetric considerations for Y90: recommendations from an international multidisciplinary working group.

The TheraSphere Global Dosimetry Steering Committee was formed in 2017 by BTG International to review existing data and address gaps in knowledge related to dosimetry. This committee is comprised of health care providers with diverse areas of expertise and perspectives on radiation dosimetry. The goal of these recommendations is to optimize glass microspheres radiation therapy for hepatocellular carcinoma while accounting for variables including disease presentation, tumour vascularity, liver function, and curative/palliative intent. The recommendations aim to unify glass microsphere users behind standardized dosimetry methodology that is simple, reproducible and supported by clinical data, with the overarching goal of improving clinical outcomes and advancing the knowledge of dosimetry.

A MAA-based dosimetric study in patients with intrahepatic cholangiocarcinoma treated with a combination of chemotherapy and 90Y-loaded glass microsphere selective internal radiation therapy.

PURPOSE: Selective internal radiation therapy (SIRT) appears to be an interesting treatment possibility for locally-advanced intrahepatic cholangiocarcinoma (ICC), yet the appropriate dosimetry has never been evaluated in this context. METHODS: We retrospectively studied data from 40 patients treated at our institution with 90Y-loaded glass microsphere SIRT combined with chemotherapy for inoperable ICC as first-line treatment. Macroaggregated albumin (MAA)-based single-photon emission computed tomography (SPECT)/computed tomography (CT) quantitative analysis was used to calculate the tumor dose (TD), healthy-injected liver dose (HILD), and injected liver dose (ILD). Response was evaluated at 3 months using the European Association for the Study of the Liver criteria. Factors associated with response and toxicity were analyzed using univariate analysis. RESULTS: We assessed a total of 35 patients (five excluded) receiving 55 injections. Mean TD was 322 ± 165Gy and mean HILD was 74 ± 24Gy for a mean ILD of 128 ± 28Gy. All but two lesions responded, with a minimal TD for responding lesions of 158Gy. Six Grade 3-4 permanent liver toxicities were observed. Mean HILD was not associated with liver toxicity (73.2 ± 25.8Gy for patients with liver toxicity and 77.8 ± 16.9Gy for patients without, ns). Only underlying Child-Pugh status (p = 0.0014) and underlying cirrhosis (p = 0.0021) were associated with liver toxicity. Median progression-free survival was 12.7 months and median overall survival (OS) was 28.6 months. Median OS was 52.7 months for patients with Child-Pugh A5 status. CONCLUSIONS: When combined with chemotherapy, SIRT is highly effective, with a TD > 158Gy. Tolerance was good except for the few patients with cirrhosis or Child-Pugh status ≥A6, who exhibited some liver toxicity. Prospective studies are warranted to confirm.

Dosimetric parameters predicting contralateral liver hypertrophy after unilobar radioembolization of hepatocellular carcinoma.

PURPOSE: This study aimed at identifying prior therapy dosimetric parameters using 99mTc-labeled macro-aggregates of albumin (MAA) that are associated with contralateral hepatic hypertrophy occurring after unilobar radioembolization of hepatocellular carcinoma (HCC) performed with 90Y-loaded glass microspheres. METHODS: The dosimetry data of 73 HCC patients were collected prior to the treatment with 90Y-loaded microspheres for unilateral disease. The injected liver dose (ILD), the tumor dose (TD) and healthy injected liver dose (HILD) were calculated based on MAA quantification. Following treatment, the maximal hypertrophy (MHT) of an untreated lobe was calculated. RESULTS: Mean MHT was 35.4 ± 40.4%. When using continuous variables, the MHT was not correlated with any tested variable, i.e., injected activity, ILD, HILD or TD except with a percentage of future remnant liver (FRL) following the 90Y-microspheres injection  (r = -0.56). MHT ≥ 10% was significantly more frequent for patients with HILD ≥ 88 Gy, (52% of the cases), i.e., in 92.2% versus 65.7% for HILD < 88 Gy (p = 0.032). MHT ≥ 10% was also significantly more frequent for patients with a TD ≥ 205 Gy and a tumor volume (VT) ≥ 100 cm3 in patients with initial FRL < 50%. MHT ≥10% was seen in 83.9% for patients with either an HILD ≥ 88 Gy or a TD ≥ 205 Gy for tumors larger than 100cm3 (85% of the cases), versus only 54.5% (p = 0.0265) for patients with none of those parameters. MHT ≥10% was also associated with FRL and the Child-Pugh score. Using multivariate analysis, the Child-Pugh score (p < 0.0001), FRL (p = 0.0023) and HILD (p = 0.0029) were still significantly associated with MHT ≥10%. CONCLUSION: This study demonstrates for the first time that HILD is significantly associated with liver hypertrophy. There is also an impact of high tumor doses in large lesions in one subgroup of patients. Larger prospective studies evaluating the MAA dosimetric parameters have to be conducted to confirm these promising results.

High impact of macroaggregated albumin-based tumour dose on response and overall survival in hepatocellular carcinoma patients treated with 90 Y-loaded glass microsphere radioembolization.

BACKGROUND & AIMS: Efficacy of radioembolization is derived from radioinduced damage, whereas tumour dosimetry is not considered as yet in prospective clinical trials. OBJECTIVES: This study evaluates the impact of tumour dose (TD), based on 99m Tc macroaggregated albumin (MAA) quantification, on response and overall survival (OS). MATERIALS AND METHODS: We consecutively included 85 patients with hepatocellular carcinoma treated with 90 Y-loaded glass microspheres. TD was calculated using a quantitative analysis of the MAA SPECT/CT. Responses were assessed after 3 months using the European Association for the Study of the Liver criteria. OS was assessed using Kaplan-Meier tests. RESULTS: Response rate was 80.3% on lesion-based analysis (n=132), and 77.5% on patient-based analysis. The response rate was only 9.1% for patients with TD <205 Gy against 89.7% for those with TD ≥205 Gy (P<10-7 ). Non-portal vein thrombosis (PVT) patients exhibited a median OS of 11.75 m (95% CI: 3-30.7 m) for TD <205 Gy, and 25 m (95% CI: 15-34.7 m) for TD ≥205 Gy (P=.0391). PVT patients exhibited a 4.35 m median OS (95% CI: 2-8 m) for TD<205 Gy, and 15.7 m (95% CI: 9.5-25.5 m) for TD ≥205 Gy, (P=.0004), with HR of 6.99. PVT patients exhibited a median OS of 3.6 m (95% CI: 2-8 m) when PVT MAA targeting was poor or with TD <205 Gy (poor candidate), vs 17.5 m (95% CI: 11-26.5 m) for the others identified as good candidates (P<.0001), with HR of 12.85. CONCLUSION: This study confirms the highly predictive value of MAA-based TD evaluation for response and OS. TD evaluation and PVT MAA targeting should be further evaluated in ongoing trials, whereas personalized dosimetry should be implemented in new trial designs.

Clinical impact of (99m)Tc-MAA SPECT/CT-based dosimetry in the radioembolization of liver malignancies with (90)Y-loaded microspheres.

Radioembolization with (90)Y-loaded microspheres is increasingly used in the treatment of primary and secondary liver cancer. Technetium-99 m macroaggregated albumin (MAA) scintigraphy is used as a surrogate of microsphere distribution to assess lung or digestive shunting prior to therapy, based on tumoral targeting and dosimetry. To date, this has been the sole pre-therapeutic tool available for such evaluation. Several dosimetric approaches have been described using both glass and resin microspheres in hepatocellular carcinoma (HCC) and liver metastasis. Given that each product offers different specific activities and numbers of spheres injected, their radiobiological properties are believed to lightly differ. This paper summarizes and discusses the available studies focused on MAA-based dosimetry, particularly concentrating on potential confounding factors like clinical context, tumor size, cirrhosis, previous or concomitant therapy, and product used. In terms of the impact of tumoral dose in HCC, the results were concordant and a response relationship and tumoral threshold dose was clearly identified, especially in studies using glass microspheres. Tumoral dose has also been found to influence survival. The concept of treatment intensification has recently been introduced, yet despite several studies publishing interesting findings on the tumor dose-metastasis relationship, no consensus has been reached, and further clarification is thus required. Nor has the maximal tolerated dose to the liver been well documented, requiring more accurate evaluation. Lung dose was well described, despite recently identified factors influencing its evaluation, requiring further assessment. Conclusion: MAA SPECT/CT dosimetry is accurate in HCC and can now be used in order to achieve a fully customized approach, including treatment intensification. Yet further studies are warranted for the metastasis setting and evaluating the maximal tolerated liver dose.

Occupational radiation exposure of medical staff performing 9°Y-loaded microsphere radioembolization.

PURPOSE: Radioembolization of liver cancer with (90)Y-loaded microspheres is increasingly used but data regarding hospital staff exposure are scarce. We evaluated the radiation exposure of medical staff while preparing and injecting (90)Y-loaded glass and resin microspheres especially in view of the increasing use of these products. METHODS: Exposure of the chest and finger of the radiopharmacist, nuclear medicine physician and interventional radiologist during preparation and injection of 78 glass microsphere preparations and 16 resin microsphere preparations was monitored. Electronic dosimeters were used to measure chest exposure and ring dosimeters were used to measure finger exposure. RESULTS: Chest exposure was very low for both products used (<10 µSv from preparation and injection). In our experience, finger exposure was significantly lower than the annual limit of 500 mSv for both products. With glass microspheres, the mean finger exposure was 13.7 ± 5.2 µSv/GBq for the radiopharmacist, and initially 17.9 ± 5.4 µSv/GBq for the nuclear medicine physician reducing to 13.97 ± 7.9 µSv/GBq with increasing experience. With resin microspheres, finger exposure was more significant: mean finger exposure for the radiopharmacist was 295.1 ± 271.9 µSv/GBq but with a reduction with increasing experience to 97.5 ± 35.2 µSv/GBq for the six most recent dose preparations. For administration of resin microspheres, the greatest mean finger exposure for the nuclear medicine physician (the most exposed operator) was 235.5 ± 156 µSv/GBq. CONCLUSION: Medical staff performing (90)Y-loaded microsphere radioembolization procedures are exposed to safe levels of radiation. Exposure is lower than that from treatments using (131)I-lipiodol. The lowest finger exposure is from glass microspheres. With resin microspheres finger exposure is acceptable but could be optimized in accordance with the ALARA principle, and especially in view of the increasing use of radioembolization.

Selective internal radiation therapy compared with sorafenib for hepatocellular carcinoma with portal vein thrombosis.

PURPOSE: Tumoural portal vein thrombosis (PVT) is a major prognostic factor in hepatocellular carcinoma (HCC). The efficacy of sorafenib, the only treatment approved at an advanced stage, is limited. Based on previous data, selective internal radiation therapy (SIRT), or (90)Y radioembolization, seems an interesting option. We aimed to compare both treatments in this population. METHODS: We retrospectively compared patients treated in two centres for HCC with tumoural PVT. We compared overall survival (OS) between patients treated with SIRT and patients treated with sorafenib. Analyses were performed before and after 1:1 matching with a propensity score for controlling indication bias, using a Cox proportional hazards model. RESULTS: A total of 151 patients were analysed, 34 patients treated with SIRT and 117 patients treated with sorafenib only. In the whole population, SIRT was associated with a higher median OS as compared with sorafenib: 18.8 vs 6.5 months (log-rank p < 0.001). There was an imbalance of baseline characteristics between patients treated by SIRT and sorafenib, which justified patient matching with use of a propensity score: 24 patients treated with SIRT could be matched with 24 patients treated with sorafenib. OS was estimated with a median of 26.2 vs 8.7 months in patients treated with SIRT vs sorafenib, respectively (log-rank p = 0.054). Before and after patient matching, the adjusted hazard ratio related to treatment by SIRT was estimated at 0.62 [95 % confidence interval (CI) 0.39-0.97] (p = 0.037) and 0.40 (95 % CI 0.19-0.82) (p = 0.013), respectively. CONCLUSION: SIRT seems more effective than sorafenib in patients presenting with HCC and tumoural PVT. This hypothesis is being tested in prospective randomized trials.