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

Escalated Segmental and Modified Radiation Lobectomy Dosing for Yttrium-90 Radioembolization of Liver-Dominant Metastatic Colorectal Cancer: 10-year Outcomes

PURPOSE

This study evaluates the safety and efficacy of escalated-dosing Yttrium-90 transarterial radioembolization (TARE) for unresectable, unablatable metastatic colorectal cancer (mCRC) to the liver.

MATERIALS AND METHODS

A retrospective review (September 2009 to March 2020) included 45 patients with liver-dominant mCRC treated with segmental Y90 or modified radiation lobectomy. Patient demographics, treatment details, adverse events, imaging response, and overall survival (OS) were analyzed. OS Prognosticators were examined using log-rank test and Cox proportional hazards regression.

RESULTS

45 patients (median age 61.4 years; 60% male) were included, with 96% ECOG 0-1. Prior treatments included primary site resection (93%), liver resection (65%), chemotherapy (60%), and ablation (27%). Extrahepatic disease was present in 51%. 71% of patients had < 25% liver tumor burden (mean tumor size = 4.8 cm). Treatment was technically successful in all cases, with 4% 30-day mortality. Adverse events were mostly low-grade, including fatigue (58%) and abdominal pain (20%). Mean neutrophil-to-lymphocyte ratio (NLR) increase was 2.9, and 33% of patients showed 50% reduction in CEA. Imaging responses (RECIST) included SD (80%), PR (18%), PD (2%), and CR (0%), with PET/CT showing 39% objective response after 4.2 months. Median OS was 41.9 months (95% CI 15.4-NE). Extrahepatic disease significantly reduced OS (15.7 vs. 44.4 months, P = .0033). Both pre- and post-NLR (HR:1.42, P = .007; HR 1.12, P = .027) were associated with worse OS. In the multivariable analysis, Pre-NLR and extrahepatic disease remained adverse prognosticators.

CONCLUSION

Y90 TARE with escalated dosing demonstrated an acceptable safety profile in heavily pretreated mCRC patients. Extrahepatic disease and pre-NLR were significant adverse prognosticators. Future studies should explore Y90 TARE dosing in mCRC patients.

Prognostic value of early response in predicting survival in hepatocellular carcinoma patients treated with selective internal radiation therapy

OBJECTIVES

This study evaluates the prognostic value of tumor response on CT at 3 months, assessed by Response Evaluation Criteria in Solid Tumors (RECIST), modified RECIST (mRECIST), and Liver Imaging Reporting and Data System Treatment Response Algorithm (LR-TRA) in patients with hepatocellular carcinoma (HCC) treated with selective internal radiation therapy (SIRT).

MATERIALS AND METHODS

A retrospective analysis was conducted on 102 HCC patients treated with SIRT between 2018 and 2020. RECIST, mRECIST, and LR-TRA were assessed at 3 months post-SIRT. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier analysis and Cox proportional-hazards models.

RESULTS

The median age was 71 years, and most patients (90%) had advanced-stage tumors (Barcelona Clinic Liver Cancer-C). After a median follow-up of 32.0 months (95% CI: 16.8-60.9), 60/102 patients died (59%), and 90/102 patients showed tumor progression (88%). Median OS was 20.4 months (95% CI: 15.4-33.0), and median PFS was 14.5 months (95% CI: 6.5-24.5); 1-year OS and PFS rates were 65.6% and 50.7%. Multivariable analysis revealed that early response according to RECIST 1.1 (HR 1.66, p = 0.30), mRECIST (HR 1.40, p = 0.215), and LR-TRA (HR 0.67, p = 0.30) were not predictors of OS. Disease progression evaluated by RECIST (HR 2.55, p < 0.001) and mRECIST (HR 2.53, p < 0.001), bilirubin levels (HR 1.03, p < 0.001), and prothrombin time (HR 0.98, p = 0.005) were predictors of OS. For PFS, neither RECIST nor mRECIST response, disease progression, nor LR-TRA viability were predictors.

CONCLUSION

In this advanced-stage HCC population, early response assessed by RECIST, mRECIST, and LR-TRA criteria did not predict OS or PFS after SIRT. However, early disease progression and liver function indicators were prognostic factors for OS.

KEY POINTS

QuestionHow well does early tumor response, assessed at 3 months post-selective internal radiation therapy (SIRT), predict survival in advanced hepatocellular carcinoma (HCC) patients? Findings Early response, assessed by RECIST, mRECIST, and LR-TRA, did not predict overall or progression-free survival; disease progression and liver function indicators were significant predictors. Clinical relevance This study highlights the limitations of early imaging criteria in predicting survival outcomes in advanced HCC post-SIRT, suggesting the need for alternative or complementary prognostic indicators to guide treatment decisions.

The relationship between yttrium-90 glass microspheres specific activity, particle density and treatment outcomes in HCC and mCRC

PURPOSE

To investigate relationships between treatment week, relative to Ytrrium-90 (90Y) glass microsphere calibration (i.e., specific activity and particle density), and outcomes for hepatocellular carcinoma (HCC) or colorectal cancer liver metastasis (mCRC).

METHODS

Multinational, multicenter study TARGET (retrospective; n = 209 HCC patients) was combined with EPOCH (phase III trial; n = 428 mCRC patients). Efficacy included overall response rate (ORR), overall survival (OS), progression-free survival (PFS), hepatic PFS, and tumour marker response rates. Safety included clinical and laboratory toxicity. Retrospective multicompartment dosimetry, tumour and normal tissue absorbed dose were available for TARGET; single compartment dosimetry was available for EPOCH.

RESULTS

No efficacy relationship was found relative to treatment week for TARGET or EPOCH. mRECIST ORR in TARGET for weeks 1 and 2 were 74/125 (59.2%) and 55/84 (65.5%), and by RECIST 1.1 in EPOCH were 54/142 (38.0%) and 15/43 (34.9%), respectively (p > 0.05). Median OS for TARGET weeks 1 and 2 were 21.4 and 20.3 months (p = 0.07), and in EPOCH were 14.9 and 16.4 months, respectively (p = 0.37). No difference in the TARGET primary endpoint of hyperbilirubinemia was noted for weeks 1 and 2, odds ratio 0.64, p = 0.59. TARGET ≥ grade 3 device-related adverse events (AEs) for weeks 1 (16.8%) and 2 (26.2%) were not significantly different (p = 0.11). EPOCH rates of ≥ grade 3 asthenia for weeks 1 (9.2%) and 2 (23.3%) were statistically different (p = 0.01).

CONCLUSIONS

No efficacy treatment benefit for week 2 versus week 1 was observed in TARGET or EPOCH, but week 2 treatment trended towards a higher rate and severity of specific AEs.

Micro-Nano Convergence-Driven Radiotheranostic Revolution in Hepatocellular Carcinoma

Radiotherapy, as an important means of treating hepatocellular carcinoma (HCC), has shown unique therapeutic advantages, especially in patients who are unable to undergo surgery or transplantation. It mainly includes external radiotherapy, transarterial radioembolization and intratumoral radioactive particle implantation. However, under the influence of factors such as the hypoxic characteristics of the liver tumor microenvironment and the radioresistance of tumor cells, the effect of radiotherapy may be unstable and may cause side effects, affecting the quality of life of patients. In recent years, with the development of nanotechnology, drug delivery systems based on micro-nanomaterials have provided new solutions for improving the effect of radiotherapy for HCC. Despite this, the application of micro-nano drug delivery systems in the treatment of HCC still faces some challenges, mainly including the in vivo safety and in vivo metabolism of micro-nano materials. This article reviews the latest progress of micro-nano materials in the treatment of HCC, especially their application in radiosensitization and their clinical translation potential. This article systematically analyzes the role of micro-nanomaterials in external or internal radiotherapy sensitization and radioimmunotherapy and explores the advantages of micro-nanomaterials in improving the treatment effect of HCC.

Temporal evolution of the LI-RADS radiation treatment response assessment on multiphase CT/MRI in patients undergoing selective internal radiation therapy for hepatocellular carcinoma

OBJECTIVES

To assess the temporal evolution and interobserver agreement of the early categories per the liver imaging reporting and data system (LI-RADS) radiation treatment response assessment (TRA) algorithm in patients receiving selective internal radiation therapy (SIRT) with Yttrium-90 for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This single-center retrospective study included consecutive patients with treatment-naïve HCC who underwent serial contrast-enhanced CT/MRI before and after SIRT. Three masked radiologists independently evaluated response at 3-6 months. Another senior radiologist assessed response at 9, 12, 15, 18, 21, 24, and > 24 months after comprehensive review of available clinical-radiological information.

RESULTS

65 patients (mean age, 66.7 ± 11.2 years; 48 men) were included. At 3-6 months after SIRT, 47.7% (31/65) of lesions were assigned to the nonprogressing category, and the remaining 52.3% (34/65) to the nonviable category. Among early nonprogressing lesions, 64.5% (20/31) regressed to the nonviable category, 25.8% (8/31) remained nonprogressing, and 9.7% (3/31) evolved into the viable category at ≥ 12 months. The nonprogressing category decreased in number over time, with 61.3% (19/31) conversion to the nonviable category at 9 months. Among the early nonviable lesions, 91.2% (31/34) remained nonviable at ≥ 12 months, and 8.8% (3/34) evolved into the viable category. Agreement for the 3-6 months LR-TR category assignment was moderate (kappa = 0.46) with CT but almost perfect (kappa = 0.85) with MRI.

CONCLUSIONS

SIRT induced a delayed and sustained response in the majority of HCC patients after ≥ 12 months. MRI demonstrated superior agreement over CT in assessing response at 3-6 months.

KEY POINTS

Question Tumor response to SIRT can change; there is limited evidence on the evolution of the imaging appearance of HCC following SIRT. Findings Sixty-four and five-tenths of early nonprogressing lesions regressed to nonviable, and 91.2% of early nonviable lesions remained free of viability. LR-TR category assignment agreement was moderate with CT but almost perfect with MRI. Clinical relevance SIRT induced a delayed and sustained response in HCC, underscoring the necessity of dynamic evaluation of long-term changes in treated lesions. MRI with subtraction imaging may be preferred over CT for long-term monitoring, which may help prevent premature retreatment decisions.

Tumoricidal dosing approach with parenchymal sparing using voxel-based dosimetry in 90Y glass microspheres treatment of hepatocellular carcinoma

OBJECTIVE

We aimed to evaluate the effect of tumor absorbed doses (TAD) on treatment response in patients with hepatocellular cancer (HCC) treated with 90Y glass microspheres. We aimed to define a cutoff value for complete response (CR).

METHODS

The voxel-based dosimetry for the treatment of 66 HCC lesions in 56 patients was analyzed retrospectively. Nineteen patients had BCLC A, 23 patients had BCLC B, and 14 patients had BCLC C disease. Treatments were grouped as selective (radiation segmentectomy and super-selective segmentectomy, n:49) and nonselective (palliative treatments for tumors occupying >2 segments, n:17). Treatment response was evaluated by mRECIST criteria, defined as CR, partial response (PR), stable lesion (SL), and progressive lesion (PL). TAD associated with CR was analyzed.

RESULTS

TAD was 525 ± 222 Gy in our cohort. Fifteen lesions had CR, 28 had PR, eight remained stable, and 15 lesions progressed. CR, PR, SL, and PL rates for selective vs. nonselective treatments were 31, 42, 12, and 14% vs. 0, 41, 11, and 47% for nonselective treatments, respectively (P:0.01). TAD was significantly associated with treatment response. Receiver operating characteristic analysis showed TAD > 475 Gy predicted CR with 100% sensitivity and 68% specificity (area under the curve = 0.83, P < 0.001). Overall survival declined as treatment response deteriorated. None of the patients had radiation-induced liver dysfunction on follow-up (6-21 months).

CONCLUSION

Higher TAD is crucial for CR. Segmentectomy with TAD > 475 Gy is associated with favorable response and better survival in HCC patients. Even for palliative treatments, as high as reasonably tolerated doses must be applied to achieve a favorable response.

Advances in Locoregional and Systemic Treatments for Hepatocellular Carcinoma

Significant advances have occurred in the locoregional and systemic therapy landscape for hepatocellular carcinoma (HCC), with the most notable being the introduction of immune checkpoint inhibitor (ICI) combinations. ICI combinations have significantly improved the overall survival of patients with unresectable HCC, affording median survival over 2 years and long-term survival exceeding 5 years in a subset of patients. Accordingly, there has been increased interest in the earlier application of systemic therapies, including (neo)adjuvant therapy in the perioperative setting or in combination with intra-arterial therapies. However, recent data failed to demonstrate improved recurrence-free survival with use of adjuvant ICI therapy. Conversely, 2 trials showed improved progression-free survival when ICI therapies were combined with transarterial chemoembolization, although data regarding the impact on overall survival are still immature. These improved outcomes raise several new questions, including which patients with liver-localized HCC should receive systemic therapy, how should this be sequenced or combined with other available therapies, and how to manage those patients with marked responses, including consideration of liver transplantation. These questions are often determined on a case-by-case basis and best made in a multidisciplinary manner considering several factors, including tumor burden, degree of liver dysfunction, performance status, and patient's long-term goals of care.

Advances and Emerging Techniques in Y-90 Radioembolization for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer deaths worldwide. Despite the high incidence of HCC, mortality remains high, with an estimated 5-year survival rate of less than 20%. Surgical resection represents a potential curative treatment for HCC; however, less than 20% of patients with HCC are candidates for surgical resection. In patients with unresectable HCC, Yttrium-90 (Y90) transarterial radioembolization (TARE) has emerged as an innovative treatment option. This locoregional therapy delivers high doses of radiation directly to liver tumors via intra-arterial injection, allowing for the targeted destruction of malignant cells while sparing surrounding healthy tissue. In this review, we will explore the latest advances in Y90 TARE for the treatment of HCC, focusing on key developments such as the following: (1) improvements in radiation lobectomy and segmentectomy techniques, (2) the introduction of personalized dosimetry, (3) the integration of combination therapies, (4) the use of imageable microspheres, (5) pressure-enabled Y90 delivery systems, and (6) the application of Y90 surrogates.

Initial Experience with Single-Session Resin-Based Transarterial Radioembolization Mapping and Treatment of Small Hepatocellular Carcinomas

BACKGROUND/OBJECTIVES

Studies have indicated that forgoing lung shunt fraction measurement in select patients undergoing Yttrium 90 (Y90) transarterial radioembolization (TARE) may be safe without sacrificing efficacy. This study evaluated the safety and efficacy of a streamlined treatment in patients with small hepatocellular carcinoma (HCC) receiving resin-based TARE.

METHODS

Patients who received single-session Y90 TARE between September 2023 and May 2024 were retrospectively evaluated. Treatment response was evaluated at the 3-month follow-up using the modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria. Adverse events (AEs) ≥ Grade 3 were recorded post-procedurally at 3 months. The time from the interventional radiology clinic visit to the procedure date was compared to patients receiving the conventional TARE treatment.

RESULTS

Ten consecutive patients were treated with 12 treatments. Each treatment targeted an isolated lesion with median size of 2.5 cm (IQR: 2.1, 2.9). Two patients received two treatments (one for treatment of a separate lesion and the other for the initial incomplete targeting of the tumor). The median delivered tumor dose was 377.7 Gy (IQR: 246.5, 570.1). No patients developed ≥ Grade 3 AEs post-TARE. Complete response was achieved in 11/12 patients (92%). The conventional cohort consisted of 60 patients, all OPTN T2 treated with radiation segmentectomy with glass microspheres. Patients undergoing SSMT had a median time from clinic visit to treatment of 26.5 days (IQR: 15.3, 39) vs. 61 days (IQR: 48, 88.8) in the conventional TARE group (p < 0.001).

CONCLUSIONS

Streamlined single-session resin-based Y90-TARE in patients with OPTN T2 stage HCC is feasible, efficacious, safe, and associated with reduced time to treatment.

Combination locoregional and systemic therapies in hepatocellular carcinoma

Locoregional therapies play a fundamental role in the treatment of patients with early and intermediate and locally advanced hepatocellular carcinomas. With encouraging recent advances in immunotherapy-based systemic therapies, locoregional therapies are being both promoted and challenged by new systemic therapy options. Combined locoregional and systemic therapies might enhance treatment outcomes compared with either option alone. This Series paper summarises the existing data on locoregional and systemic therapies for hepatocellular carcinoma, and discusses evidence from studies investigating their combination with a focus on their synergistic efficacy and safety.

Hepatocellular Carcinoma with Vascular Invasion Treated with Resin Yttrium-90 Transarterial Radioembolization Using Single Compartment Dosimetry

PURPOSE

To report outcomes in hepatocellular carcinoma (HCC) patients with lobar and segmental vascular invasion treated with resin Yttrium-90 transarterial radioembolization (Y90-TARE) with single-compartment MIRD (Medical Internal Radiation Dose) model.

MATERIALS AND METHODS

This was a retrospective IRB approved study of patients with a diagnosis of HCC with vascular invasion undergoing resin Y90-TARE from 2014 to 2022 (n = 61). Patients with Body Surface Area dosimetry (n = 20), main portal vein invasion (n = 6) and patients with an ECOG of > 2 were excluded (n = 1) with a final cohort of 34 patients.

RESULTS

Study population consisted of 34 patients, median age 62 years [60-71], tumor size 4.2 (2.8-7.4) cm, and 82% male. The median prescribed dose was 170 (126-200) Gy. The objective response rate at 6 months was 67% and disease control rate was 72%. The median survival was 18 months, median progression-free survival was 9.8 months. The 1- and 3-year survival rates were 76% and 57% in patients prescribed > 180 Gy, compared to 29% and 15% in patients with < 180 Gy (p = 0.01). Five of 15 Childs-Pugh A, ECOG < 1 patients (33%) were downstaged to resection, with complete pathologic necrosis in 40%, and 1 and 3-year survival rates of 100%. Grade-3 adverse events were seen in only 5/34 (15%), with no grade-4 or 5 adverse events.

CONCLUSION

Resin Y90-TARE using single compartment MIRD model for HCC with segmental and lobar vascular invasion can result in downstaging to resection in 33% of patients and higher prescribed doses (> 180 Gy) result in improved survival.

Clinical and dosimetric considerations for yttrium-90 glass microspheres radioembolization of intrahepatic cholangiocarcinoma, metastatic colorectal carcinoma, and metastatic neuroendocrine carcinoma: recommendations from an international multidisciplinary working group

PURPOSE

The TheraSphere Global Steering Committee reconvened to review clinical data and address knowledge gaps related to treatment and dosimetry in non-HCC indications using Yttrium-90 (90Y) glass microspheres.

METHODS

A PubMed search was performed. References were reviewed and adjudicated by the Delphi method. Recommendations were graded according to the degree of recommendation and strength of consensus. Dosimetry focused on a mean dose approach, i.e., aiming for an average dose over either single or multicompartment volumes of interests. Committee discussion and consensus focused on optimal patient selection, disease presentation, liver function, tumour type, tumour vascularity, and curative/palliative treatment intent for intrahepatic cholangiocarcinoma (iCCA) and colorectal and neuroendocrine carcinoma liver metastases (mCRC, mNET).

RESULTS

For all indications, single compartment average perfused volume absorbed dose ≥ 400 Gy is recommended for radiation segmentectomy and 150 Gy for radiation lobectomy. Single compartment 120 Gy for uni- and bilobar treatment reflects current clinical practice, which results in variable tumour and normal tissue absorbed doses. Therefore, multicompartment dosimetry is recommended for uni- and bilobar treatment, aiming for maximum 75 Gy to normal tissue and 150-200 Gy (mCRC, mNET), ≥ 205 (iCCA) tumour absorbed doses. These dose thresholds are preliminary and should be used with caution accounting for patient specific characteristics.

CONCLUSION

Consensus recommendations are provided to guide clinical and dosimetry approaches for 90Y glass microsphere radioembolization in iCCA, mCRC and mNET.

CLINICAL TRIAL NUMBER

not applicable.

Long-term outcomes of Yttrium-90 transarterial radioembolization for patients with hepatocellular carcinoma

AIMS

We retrospectively assessed the long-term outcomes of Yttrium-90 (90Y) transarterial radioembolization (TARE) for hepatocellular carcinoma (HCC), focusing on overall survival (OS), radiological response, and safety.

METHODS

We included patients with HCC treated with 90Y TARE at a single center between January 2012 and December 2021 with measurable lesions and a minimum of 2 years of follow-up. Only the former was analyzed for patients with multiple TARE. The primary endpoints were long-term OS, radiological response, and safety; the secondary endpoints included predictors of OS and response, with emphasis on dosimetry. The collected data included demographics, laboratory test results, liver function, and tumor staging. Radiological response was evaluated 3-6 months post-TARE using the modified RECIST (mRECIST) criteria. OS was calculated from TARE until death or censoring. Univariate logistic regression was used to identify the predictors of complete radiological response and OS. Dosimetry was analyzed to determine correlations with mRECIST response.

RESULTS

Among 142 patients (median age 66.8, cirrhotic 92.3%; M: F = 121:21), a median OS of 16.68 months was achieved, with a complete radiological response in 31% (44/142). OS was strongly correlated with radiological response (p < 0.001). Absorbed dose ≥ 234.6 Gy was associated with complete response (p = 0.017) but not with survival (p = 0.102). Rising alpha-fetoprotein levels (p = 0.017) and worsening Child-Pugh scores post-TARE (p = 0.044) were independent predictors of mortality.

CONCLUSION

A complete radiological response is crucial for long-term survival, highlighting the need for dosimetry optimization in TARE for HCC.

Radioembolization as a Spearhead Treatment of Hepatocellular Carcinoma with Localized Portal Vein Tumor Thrombosis (RESOLVE): Protocol for an Open-label, Multi-center, Single-arm Trial

PURPOSE

To evaluate the efficacy, safety, and clinical course following ablative radioembolization with glass microspheres for hepatocellular carcinoma (HCC) with localized portal vein tumor thrombosis (PVTT) in patients with well-preserved liver function.

MATERIALS AND METHODS

This is a prospective, open-label, multi-center, single-arm, phase II trial. Key inclusion criteria are unilobar HCC, PVTT confined to the ipsilateral lobe (Vp1-3), no extrahepatic spread, Child-Pugh class A, and a performance status of ≤ 1. Main exclusion criteria are hepatic venous tumor thrombus, bile duct invasion, and massive arterioportal shunting. Depending on the extent of the tumor and PVTT, patients will undergo radiation segmentectomy, modified radiation lobectomy, or ablative lobar treatment, while adhering to dose limits for the non-tumorous liver and lung. The primary outcome measure is overall survival, with the overall survival rate at two years provided as the summary measurement.

STATISTICS

This study will enroll 30 patients to explore the efficacy and safety of ablative radioembolization for HCC with localized PVTT. Efficacy will be evaluated by intention-to-treat and per-protocol populations. Safety will be assessed for all patients who received radioembolization at any dose.

EXPECTED GAIN OF KNOWLEDGE

This study aims to address the potential of ablative radioembolization as a definitive or effective downstaging treatment for HCC with localized PVTT, where locoregional treatments may be more beneficial than systemic treatments. The results will help establish treatment outcomes that can serve as a standard for future comparative studies and contribute to the standardization of radioembolization approaches for HCC with localized PVTT.

TRIAL REGISTRATION

ClinicalTrials.gov ( https://classic.

CLINICALTRIALS

gov/ct2/show/NCT06166576 ). Identifier: NCT06166576.

TACE vs. TARE for HCC ≥ 8 cm: A propensity score analysis

OBJECTIVE

This study aimed to compare transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) as first-line treatments for unresectable HCC > 8 cm.

METHODS

This retrospective study analyzed 129 HCC patients with tumor diameters greater than 8 cm from January 2010 to December 2021, including 40 patients who received TARE, and 89 patients treated with TACE as primary treatment. Following Propensity Score Matching (PSM), 40 patients from each group were harmonized for baseline characteristics. Tumor responses were evaluated using mRECIST criteria, and survival outcomes were compared between treatment groups using Kaplan-Meier curves and the Log-rank test.

RESULTS

There was no significant difference in the objective response rate (ORR) and disease control rate (DCR) at 3, 6, and 12 months between the two groups; ORR and DCR were 72.6%, 83.1% in TACE group vs. 72.5%. 87.5% in TARE group for best tumor response (p-values: 0.625 and 0.981, respectively). Overall survival (OS) and progression-free survival (PFS) between the two groups were comparable pre- and post-PSM. After PSM, the OS was 33.2 months (20.0-58.6) in TACE group and 38.1 months (13.8-98.1) in TARE group (p = 0.53), while PFS was 11.5 months (7.7-18.4) and 9.1 months (5.2-23.8) respectively. After PSM, post-embolization syndrome developed more in TACE group (100% vs. 75%, p = 0.002). Major adverse events were 72% in TACE group vs. 5% in TARE group (p < 0.001).

CONCLUSIONS

TARE and TACE offer comparable efficacy in managing large HCC, with TARE providing a safer profile, suggesting its consideration as a preferable initial therapeutic approach for unresectable HCC patients with tumors larger than 8 cm.

Discordance between 90Y-PET/CT(MR)-estimated activity and dose calibrator measured administered activity: an international study in SIRT patients treated with resin and glass microspheres

PURPOSE

Therapeutic administration of 90Y-loaded microspheres is routinely used for primary and secondary liver tumours. For activity-based therapeutic prescription the activity must be within 10% of the intended activity. Previous studies reported significant discrepancies between manufacturer-declared vial activities and both experimental and Monte-Carlo assessments, greater than 10%, for resin/glass 90Y-microspheres. The objective of this work was to investigate whether these discrepancies were also seen in patients.

METHODS

We analysed patient 90Y-PET reconstructions (99 glass and 15 resin microspheres) from 4 different institutions and 4 different systems. We considered tail-fitting background scaling (TFBS) and absolute scaling (ABS), for scatter correction. Residuals after therapeutic injection were measured. Eighty-one patients were imaged with PET/CT and 33 with PET/MR. The PET measured activity (APET) was assessed in the whole liver. The ratio APET/Acalibrator was calculated for each patient, where Acalibrator was the injected activity measured by the dose calibrator corrected for residual and lung shunt.

RESULTS

Quantification ratio between calibrators and PET was significantly different from 1, regardless of the scatter correction used. In glass microspheres, the mean APET/CT/Acalibrator was 0.84 ± 0.06 for TFBS and 0.90 ± 0.06 for ABS (0.66 ± 0.09 and 0.76 ± 0.07 for (APET/MR/Acalibrator)). The mean APET/CT/Acalibrator ratio for resin microspheres was 1.16 ± 0.09 for TFBS and 1.30 ± 0.12 for ABS.

CONCLUSIONS

We observed in patients similar activity discrepancies as reported for vials, with a relative difference of 44 ± 16% between glass and resin 90Y-loaded microspheres. In 90Y hepatic radioembolization, the 10% accuracy prerequisite on knowing the administered therapeutic activity is then unlikely to be met.

EASL Clinical Practice Guidelines on the management of hepatocellular carcinoma

Liver cancer is the third leading cause of cancer-related deaths worldwide, with hepatocellular carcinoma (HCC) accounting for approximately 90% of primary liver cancers. Advances in diagnostic and therapeutic tools, along with improved understanding of their application, are transforming patient treatment. Integrating these innovations into clinical practice presents challenges and necessitates guidance. These clinical practice guidelines offer updated advice for managing patients with HCC and provide a comprehensive review of pertinent data. Key updates from the 2018 EASL guidelines include personalised surveillance based on individual risk assessment and the use of new tools, standardisation of liver imaging procedures and diagnostic criteria, use of minimally invasive surgery in complex cases together with updates on the integrated role of liver transplantation, transitions between surgical, locoregional, and systemic therapies, the role of radiation therapies, and the use of combination immunotherapies at various stages of disease. Above all, there is an absolute need for a multiparametric assessment of individual risks and benefits, considering the patient's perspective, by a multidisciplinary team encompassing various specialties.

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.

Streamlining Radioembolization without Lung Shunt Estimation versus Regular Radioembolization in Patients with Hepatocellular Carcinoma within the Milan Criteria

PURPOSE

To assess the effectiveness and safety of streamlining transarterial radioembolization (S-TARE) without lung shunt fraction estimation using nuclear medicine imaging, compared with regular transarterial radioembolization (R-TARE), for patients with hepatocellular carcinoma (HCC) within the Milan criteria.

MATERIALS AND METHODS

Between January 2012 and December 2022, 100 consecutive patients with HCC within the Milan criteria underwent R-TARE (n = 38) or S-TARE (n = 62) and were retrospectively analyzed. Adverse events, complete response (CR) rates, and time to progression (TTP) by the modified Response Evaluation Criteria in Solid Tumours (mRECIST) and localized mRECIST following each treatment were compared using the Fisher exact test and Kaplan-Meier curve analyses with covariate adjustment.

RESULTS

Serious adverse events ≥ Grade 3 occurred in 3 (7.9%, 3/38) and 2 (3.2%, 2/62) patients following R-TARE and S-TARE, respectively (P = .365). No patients developed radiation pneumonitis. Among the 84 patients treated with glass microspheres, the CR rates were not significantly different after R-TARE (96.9%, 31/32) and S-TARE (90.4%, 47/52) (P = .400). There was no significant difference in TTP by mRECIST between R-TARE and S-TARE (unadjusted P = .400, adjusted P = .712). For patients with a single HCC, no significant difference was observed in TTP by localized mRECIST (unadjusted P = .090, adjusted P = .242). In the 16 patients treated with resin microspheres, the CR rates were 66.7% (4/6) for R-TARE and 90% (9/10) for S-TARE, respectively (P = .518).

CONCLUSIONS

S-TARE using yttrium-90 glass or resin microspheres was as effective and safe as R-TARE for HCC within the Milan criteria.

Do we need dosimetry for the optimization of theranostics in CNS tumors?

Radiopharmaceutical theranostic treatments have grown exponentially worldwide, and internal dosimetry has attracted attention and resources. Despite some similarities with chemotherapy, radiopharmaceutical treatments are essentially radiotherapy treatments, as the release of radiation into tissues is the determinant of the observed clinical effects. Therefore, absorbed dose calculations are key to explaining dose-effect correlations and individualizing radiopharmaceutical treatments. The present article introduces the basic principles of internal dosimetry and provides an overview of available loco-regional and systemic radiopharmaceutical treatments for central nervous system (CNS) tumors. The specific characteristics of dosimetry as applied to these treatments are highlighted, along with their limitations and most relevant results. Dosimetry is performed with higher precision and better reproducibility than in the past, and dosimetric data should be systematically collected, as treatment planning and verification may help exploit the full potential of theranostic of CNS tumors.

Using Voxel-Based Dosimetry to Evaluate Sphere Concentration and Tumor Dose in Hepatocellular Carcinoma Treated with Yttrium-90 Radiation Segmentectomy with Glass Microspheres

PURPOSE

To utilize voxel-based dosimetry following radiation segmentectomy (RS) to understand microsphere distribution and validate current literature regarding radiologic and pathologic outcomes.

MATERIALS AND METHODS

A retrospective, single-center analysis of patients with solitary hepatocellular carcinoma (N = 56) treated with yttrium-90 (90Y) RS with glass microspheres (Therasphere; Boston Scientific, Marlborough, Massachusetts) from 2020 to 2022 was performed. Posttreatment voxel-based dosimetry was evaluated using Mirada DBx Build 1.2.0 Simplicit90Y software (Boston Scientific) and utilized to calculate sphere concentration to tumor as well as D70 (minimum dose to 70% total tumor volume), D90, and D99. Time to progression (TTP), treatment response, and adverse events were studied.

RESULTS

Fifty-six solitary tumors were analyzed with a median tumor diameter of 3.4 cm (range, 1.2-6.8 cm) and median tumor absorbed dose of 732 Gy (range, 252-1,776 Gy). Median sphere activity (SA) at the time of delivery was 1,446 Bq (range, 417-2,621 Bq). Median tumor sphere concentration was 12,868 spheres/mL (range, 2,655-37,183 spheres/mL). Sphere concentration into tumor and normal tissue was inversely correlated with perfused treatment volume (R2 = 0.21 and R2 = 0.39, respectively). Of the 51 tumors with posttreatment imaging, objective response was noted in 49 patients (96%) and complete response in 42 patients (82%). The median TTP was not reached with a 2-year progression rate of 11%. Fifteen patients underwent liver transplant. Median tumor necrosis was 99% (range, 80%-100%). Lower tumor volumes and higher D99 were associated with complete pathologic necrosis (P < .001 and P = .022, respectively).

CONCLUSIONS

Voxel-based dosimetry following 90Y radioembolization can be utilized to account for sphere deposition and distribution into tumor. Ablative RS with high SA yields durable radiologic and pathologic outcomes.

Single-Session Ablative Transarterial Radioembolization for Patients with Hepatocellular Carcinoma to Streamline Care: An Initial Experience

PURPOSE

Transarterial radioembolization (TARE) for hepatocellular carcinoma (HCC) is performed after a mapping angiogram involving infusion of radiolabeled macroaggregated albumin to assess for non-target embolization and pulmonary shunting. The purpose of this case series was to evaluate the safety and feasibility of single-session TARE without the initial procedure.

MATERIALS AND METHODS

A single-institution case series of 16 consecutive procedures on 15 patients with 18 tumors who underwent an attempted single-session TARE procedures with glass microspheres are presented. A lung shunt fraction (LSF) of 5% was assumed for planning purposes.

RESULTS

Sixty-seven percent (10/15) of patients were male with a median age of 72 years. Median tumor size was 2.5 cm (IQR 2.0-3.2 cm). Sixteen of the 18 targeted tumors were untreated prior to the single-session TARE. Rate of technical success was 88% (14/16). Two patients did not ultimately receive a single-session TARE due to intraprocedural findings. The mean administered activity was 2.0 GBq, and the mean MIRD dose was 464 Gy based on pre-treatment anatomic imaging and 800 Gy based on cone-beam CT. There were no cases of radiation pneumonitis. Mean post-procedural calculated lung dose was 4.9 Gy (range 3.1-9.3) based on SPECT.

CONCLUSIONS

An initial experience with single-session TARE using Y-90 glass microspheres without pre-procedural mapping angiography and lung shunt estimation demonstrates that it is a feasible and safe treatment option for select patients with small (< 5 cm) HCC.

LEVEL OF EVIDENCE IV

Level 4 case series.

High-Dose-Rate Yttrium-90 (90Y) Episcleral Plaque Brachytherapy for Iris and Iridociliary Melanoma

Purpose

To describe a pilot study on the use of single-session, high-dose-rate, Food and Drug Administration-cleared, yttrium-90 (Y90) plaque brachytherapy for iris and iridociliary melanoma.

Design

A single-center, clinical case series.

Participants

Six consecutive patients were included in this study. Each was diagnosed with an iris or iridociliary melanoma based on clinical examination with or without biopsy.

Methods

Each tumor was staged according to the American Joint Committee on Cancer criteria and received Y90 eye plaque brachytherapy. The main variables were tumor size, patient age, sex, and method of diagnosis (clinical or biopsy). Surgical techniques, treatment durations, and ocular side effects were recorded. Local control was defined as a lack of tumor growth or regression determined by clinical examinations, including slit-lamp and gonio photography, as well as high-frequency ultrasound measurements. Toxicity parameters included acute and short-term corneal/scleral change, anterior segment inflammation, and cataract progression.

Main Outcome Measures

Local and systemic cancer control, tumor regression, visual acuity, as well as radiation-related normal tissue toxicity.

Results

High-dose-rate Y90 plaque brachytherapy was used to treat small (American Joint Committee on Cancer cT1) category melanomas. Single-surgery high-dose-rate irradiations were performed under anesthesia. Because of short treatment durations, high-dose-rate Y90 did not require the additional procedures used for low-dose-rate plaque (e.g., sutures, amniotic membrane epicorneal buffering, Gunderson flaps, and second surgeries for plaque removal). Only conjunctival recession was used to avoid normal tissue irradiation. High-dose-rate Y90 treatment durations averaged 8.8 minutes (median, 7.9; range, 5.8-12.9). High-dose-rate Y90 brachytherapy was associated with no periorbital, corneal (Descemet folds), or conjunctival edema. There was no acute or short-term anterior uveitis, secondary cataract, scleropathy, radiation retinopathy, maculopathy, or optic neuropathy. The follow-up was a mean of 16.0 (range 12-24) months. Evidence of local control included a lack of expansion of tumor borders (n = 6, 100%), darkening with or without atrophy of the tumor surface (n = 5/6, 83%), and a mean 24.5% reduction in ultrasonographically measured tumor thickness. There were no cases of metastatic disease.

Conclusions

High-dose-rate Y90 brachytherapy allowed for single-surgery, minimally invasive, outpatient irradiation of iris and iridociliary melanomas.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Conversion Therapy to Transplant or Surgical Resection in Patients with Unresectable Hepatocellular Carcinoma Treated with Boosted Dose of Yttrium-90 Radiation Segmentectomy

BACKGROUND/OBJECTIVES

The aim of this study was to assess the efficacy of boosted dose yttrium-90 radioembolization (TARE) as a modality for conversion therapy to transplant or surgical resection in patients with unresectable hepatocellular carcinoma (HCC).

METHODS

In this single-center retrospective study, all patients with a diagnosis of HCC who were treated with boosted dose TARE (>190 Gy) between January 2013 and December 2023 were reviewed. Treatment response and decrease in tumor size were assessed with the RECIST v1.1 and mRECIST criteria. Milan and University of California, San Francisco (UCSF), criteria were used to determine transplant eligibility, and Barcelona Clinic Liver Cancer (BCLC) surgical resection recommendations were used to evaluate tumor resectability.

RESULTS

Thirty-eight patients with primary HCC who were treated with boosted dose TARE were retrospectively analyzed. The majority of the patients were Child-Pugh A (n = 35; 92.1%), BCLC C (n = 17; 44.7%), and ECOG performance status 0 (n = 25; 65.8%). The mean sum of the target lesions was 6.0 cm (standard deviation; SD = 4.0). The objective response rate (ORR) was 31.6% by RECIST and 84.2% by mRECIST. The disease control rate (DCR) was 94.7% by both RECIST and mRECIST. Among patients outside of Milan or UCSF, 13/25 (52.0%, Milan) and 9/19 (47.4%, UCSF) patients were successfully converted to within transplant criteria. Of patients who were initially unresectable, conversion was successful in 7/26 (26.9%) patients.

CONCLUSIONS

This study provides further real-world data demonstrating that boosted-dose TARE is an effective modality for conversion of patients with unresectable HCC to transplant or resection.

Measure of 90Y-glass microspheres residue post-TARE using PET/CT and potential impact on tumor absorbed dose in comparison 99mTc-MAA SPECT/CT dosimetry

BACKGROUND

Transarterial radio-embolization (TARE) became a routine procedure for non-resectable liver tumor mainly hepatocellular carcinoma (HCC). Personalized dosimetry to the index lesion increased tumor response rate. However, there is no requirement to measure the precise activity injected during TARE. We measured 90Y-glass microspheres residue (90Y-Res) in the application system after TARE and assessed its potential impact on the tumor absorbed dose (AD) previously planned with 99mTc MAA SPECT/CT.

METHODS

We measured 90Y-Res using PET/CT in all patients that underwent TARE using 90Y-glass-microspheres for non-resectable liver tumors over one year.

RESULTS

90Y-Res was measured in 34 patients (HCC n = 22) with 61 injections, 93.1 ± 94.6 MBq [2-437] that was 4.8 ± 3.5% [0.2-13.7] in comparison to the activity measured in the sealed TheraSphere™ vial (ρ = 0.697; p < 0.001).

CONCLUSION

We reported an average of 5% 90Y-Res using PET/CT after TARE with the strongest association to the activity in the TheraSphere™ vial. Therefore, when a high 90Y-Res is suspected on the survey meter, a 90Y-PET/CT scan of 90Y-Res might be useful as a first step to estimate if the target lesion received the recommended AD, especially in HCC patients with borderline tumor dosimetry on the pre-treatment 99mTc-MAA SPECT/CT.

Dose-Response Relationship in Patients with Liver Metastases from Neuroendocrine Neoplasms Undergoing Radioembolization with 90Y Glass Microspheres

The benefit of multicompartment dosimetry in the radioembolization of neuroendocrine neoplasms is not firmly established. We retrospectively assessed its potential with patient outcome. Methods: Forty-three patients were eligible. The association of mean absorbed dose (MAD) for tumors and treatment response was tested per lesion with a receiver operating characteristic curve analysis, and the association of MAD with progression-free survival (PFS) and overall survival was tested per patient using uni- and multivariate Cox regression analyses. Results: The area under the curve for treatment response based on MAD was 0.79 (cutoff, 196.6 Gy; P < 0.0001). For global PFS, grade (grade 2 vs. 1: hazard ratio [HR], 2.51; P = 0.042; grade 3 vs. 1: HR, 62.44; P < 0.001), tumor origin (HR, 6.58; P < 0.001), and MAD (HR, 0.998; P = 0.003) were significant. For overall survival, no prognostic parameters were significant. Conclusion: In line with prior publications, a MAD of more than 200 Gy seemed to favor treatment response. MAD was also associated with PFS and may be of interest for radioembolization planning for neuroendocrine neoplasm patients.

Designing polysaccharide materials for tissue repair and regeneration

Tissue repair and regeneration are critical processes for maintaining the integrity and function of various organs and tissues. Recently, polysaccharide materials and protein materials have garnered interest for use in tissue repair strategies. However, polysaccharides are more stable and unaffected by temperature and pH changes compared to proteins, and some polysaccharides can provide stronger mechanical support, which is particularly important for constructing tissue-engineered scaffolds and wound dressings. This Review provides an in-depth overview of the origins of polysaccharides, the advantages of polysaccharide materials, and processing and design strategies. In addition, the potential of polysaccharide materials for the restoration of tissues such as skin, heart, and nerves is highlighted. Finally, we discuss in depth the challenges that polysaccharide materials still face in tissue repair, such as the stability of the material, regulating mechanical characteristics and deterioration rates under different conditions. To achieve more effective tissue repair and regeneration, future research must focus on further improving the characteristics and functionalities of polysaccharide materials.

Clinical Results of Holmium-166 Radioembolization with Personalized Dosimetry for the Treatment of Hepatocellular Carcinoma

Transarterial radioembolization (TARE) with 166Ho-loaded microspheres is an established locoregional treatment for hepatocellular carcinoma (HCC), introduced in 2010. This study evaluates the clinical outcome of patients with HCC who underwent 166Ho-TARE with personalized dosimetry. Twenty-seven patients with 36 TARE procedures were analyzed. Treatment planning, execution, and evaluation was possible without complications in all cases. At the 3-month follow-up, disease control in the treated liver was achieved in 81.8% of patients (complete remission, partial remission, and stable disease in 36.4%, 31.8%, and 13.6%, respectively). The median overall survival (OS) was 17.2 months, and progression-free survival (PFS) in the treated liver was 11 months. Statistically significant positive correlations were observed between the achieved radiation dose for the tumor and both PFS (r = 0.62, p < 0.05) and OS (r = 0.48, p < 0.05), suggesting a direct dose-response relationship. The calculated achieved dose was 8.25 Gy lower than the planned dose, with relevant variance between planned and achieved doses in individual cases. These results confirm the efficacy of the 166Ho-TARE holmium platform and underscore the potential of voxel-based, personalized dosimetry to improve clinical outcomes.

Image-guided percutaneous strategies to improve the resectability of HCC: Portal vein embolization, liver venous deprivation, or radiation lobectomy?

Despite considerable advances in surgical technique, many patients with hepatic malignancies are not operative candidates due to projected inadequate hepatic function following resection. Consequently, the size of the future liver remnant (FLR) is an essential consideration when predicting a patient's likelihood of liver insufficiency following hepatectomy. Since its initial description 30 years ago, portal vein embolization has become the standard of care for augmenting the size and function of the FLR preoperatively. However, new minimally invasive techniques have been developed to improve surgical candidacy, chief among them liver venous deprivation and radiation lobectomy. The purpose of this review is to discuss the status of preoperative liver augmentation prior to resection of hepatocellular carcinoma with a focus on these three techniques, highlighting the distinctions between them and suggesting directions for future investigation.

Are survival outcomes dependent on the tumour dose threshold of 139 Gy in patients with chemorefractory metastatic colorectal cancer treated with yttrium-90 radioembolization using glass particles? A real-world single-centre study

OBJECTIVES

To compare the survival and objective response rate (ORR) of the patients receiving estimated tumour absorbed dose (ETAD) <140 Gy versus ETAD ≥140 Gy in patients with advanced chemorefractory colorectal carcinoma liver metastases (CRCLM) treated with yttrium-90 transarterial radioembolization (90Y TARE).

METHODS

Between August 2016 and August 2023 adult patients with unresectable, chemorefractory CRCLM treated with 90Y TARE using glass particles, were retrospectively enrolled. Primary outcomes were overall survival (OS) and hepatic progression free survival (hPFS). Secondary outcome was ORR.

RESULTS

A total of 40 patients with a mean age of 66.2 ± 7.8 years met the inclusion criteria. Mean ETAD for group 1 (ETAD <140 Gy) and group 2 (ETAD ≥140) were 131.2 ± 17.4 Gy versus 195 ± 45.6 Gy, respectively. The mean OS and hPFS for group 1 versus group 2 were 12 ± 10.3 months and 8.1 ± 9.3 months versus 9.3 ± 3 months and 7.1 ± 8.4 months, respectively and there were no significant differences (P = .181 and P = .366, respectively). ORR did not show significant difference between the groups (P = .432).

CONCLUSION

In real-world practice, no significant difference was found in OS, hPFS, and ORR between patients who received ETAD <140 Gy versus ETAD ≥140 Gy in patients with CRCLM, in this series.

ADVANCES IN KNOWLEDGE

This study demonstrated that increased tumour absorbed doses in radioembolization may not provide additional significant advantage for OS and hPFS for patients with CRCLM.

Adjuvant holmium-166 radioembolization after radiofrequency ablation in early-stage hepatocellular carcinoma patients: a dose-finding study (HORA EST HCC trial)

PURPOSE

The aim of this study was to investigate the biodistribution of (super-)selective trans-arterial radioembolization (TARE) with holmium-166 microspheres (166Ho-MS), when administered as adjuvant therapy after RFA of HCC 2-5 cm. The objective was to establish a treatment volume absorbed dose that results in an absorbed dose of ≥ 120 Gy on the hyperemic zone around the ablation necrosis (i.e., target volume).

METHODS

In this multicenter, prospective dose-escalation study in BCLC early stage HCC patients with lesions 2-5 cm, RFA was followed by (super-)selective infusion of 166Ho-MS on day 5-10 after RFA. Dose distribution within the treatment volume was based on SPECT-CT. Cohorts of up to 10 patients were treated with an incremental dose (60 Gy, 90 Gy, 120 Gy) of 166Ho-MS to the treatment volume. The primary endpoint was to obtain a target volume dose of ≥ 120 Gy in 9/10 patients within a cohort.

RESULTS

Twelve patients were treated (male 10; median age, 66.5 years (IQR, [64.3-71.7])) with a median tumor diameter of 2.7 cm (IQR, [2.1-4.0]). At a treatment volume absorbed dose of 90 Gy, the primary endpoint was met with a median absorbed target volume dose of 138 Gy (IQR, [127-145]). No local recurrences were found within 1-year follow-up.

CONCLUSION

Adjuvant (super-)selective infusion of 166Ho-MS after RFA for the treatment of HCC can be administered safely at a dose of 90 Gy to the treatment volume while reaching a dose of ≥ 120 Gy to the target volume and may be a favorable adjuvant therapy for HCC lesions 2-5 cm.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03437382 . (registered: 19-02-2018).

Combination and Optimal Sequencing of Systemic and Locoregional Therapies in Hepatocellular Carcinoma: Proceedings from the Society of Interventional Radiology Foundation Research Consensus Panel

Hepatocellular carcinoma, historically, has had a poor prognosis with very few systemic options. Furthermore, most patients at diagnosis are not surgical candidates. Therefore, locoregional therapy (LRT) has been widely used, with strong data supporting its use. Over the last 15 years, there has been progress in the available systemic agents. This has led to the updated Barcelona Clinic Liver Cancer (BCLC) algorithm's inclusion of these new systemic agents, with advocacy of earlier usage in those who progress on LRT or have tumor characteristics that make them less likely to benefit from LRT. However, neither the adjunct of LRT nor the specific sequencing of combination therapies is addressed directly. This Research Consensus Panel sought to highlight research priorities pertaining to the combination and optimal sequencing of LRT and systemic therapy, assessing the greatest needs across BCLC stages.

Production and regulatory issues for theranostics

Theranostics has become a major area of innovation and progress in cancer care over the last decade. In view of the introduction of approved therapeutics in neuroendocrine tumours and prostate cancer in the last 10 years, the ability to provide access to these treatments has emerged as a key factor in ensuring global benefits from this cancer therapy approach. In this Series paper we explore the issues that affect access to and availability of theranostic radiopharmaceuticals, including supply and regulatory issues that might affect the availability of theranostic treatments for patients with cancer.

A Post-International Gastrointestinal Cancers' Conference (IGICC) Position Statements

Hepatocellular carcinoma (HCC), the most prevalent liver tumor, is usually linked with chronic liver diseases, particularly cirrhosis. As per the 2020 statistics, this cancer ranks 6th in the list of most common cancers worldwide and is the third primary source of cancer-related deaths. Asia holds the record for the highest occurrence of HCC. HCC is found three times more frequently in men than in women. The primary risk factors for HCC include chronic viral infections, excessive alcohol intake, steatotic liver disease conditions, as well as genetic and family predispositions. Roughly 40-50% of patients are identified in the late stages of the disease. Recently, there have been significant advancements in the treatment methods for advanced HCC. The selection of treatment for HCC hinges on the stage of the disease and the patient's medical status. Factors such as pre-existing liver conditions, etiology, portal hypertension, and portal vein thrombosis need critical evaluation, monitoring, and appropriate treatment. Depending on the patient and the characteristics of the disease, liver resection, ablation, or transplantation may be deemed potentially curative. For inoperable lesions, arterially directed therapy might be an option, or systemic treatment might be deemed more suitable. In specific cases, the recommendation might extend to external beam radiation therapy. For all individuals, a comprehensive, multidisciplinary approach should be adopted when considering HCC treatment options. The main treatment strategies for advanced HCC patients are typically combination treatments such as immunotherapy and anti-VEGFR inhibitor, or a combination of immunotherapy and immunotherapy where appropriate, as a first-line treatment. Furthermore, some TKIs and immune checkpoint inhibitors may be used as single agents in cases where patients are not fit for the combination therapies. As second-line treatments, some treatment agents have been reported and can be considered.

Implications of lung shunt fraction calculation discrepancy in Yttrium-90 radioembolization treatment from 2D planar vs 3D single photon emission CT imaging

The safety and efficacy of Yttrium-90 (Y-90) radio-embolization therapy is partly dependent on the lung shunt fraction (LSF). There may be a notable disparity between LSF when calculated using 2D planar imaging vs 3D single photon emission CT (SPECT); this can affect the total allowable Y-90 dose delivered and therefore change the effectiveness of the procedure. The case presented demonstrates an 81% decrease in LSF when calculated by SPECT as compared to 2D planar imaging. This case highlights the importance of considering the imaging technique and the potential discrepancies that can arise between planar and SPECT imaging in LSF assessment.

Efficacy of Yttrium-90 Transarterial Radioembolisation in Advanced Hepatocellular Carcinoma: An Experience With Hybrid Angio-Computed Tomography and Glass Microspheres

Background

Hepatocellular carcinoma is one of the most common malignancies worldwide. Transarterial radioembolisation (TARE) involves selective intra-arterial administration of microspheres loaded with a radioactive compound like Yttrium-90 (Y-90). Conventionally, C-arm-based cone-beam computed tomography has been extensively used during TARE. However, angio-computed tomography (CT) is a relatively new modality which combines the advantages of both fluoroscopy and fCT. There is scarce literature detailing the use of angio-CT in Y90 TARE.

Methods

This was a retrospective study of primary liver cancer cases in which the TARE procedure was done from November 2017 to December 2021. Glass-based Y-90 microspheres were used in all these cases. All the cases were performed in the hybrid angio-CT suite. A single photon emission computed tomography-computed comography (SPECT-CT) done postplanning session determined the lung shunt fraction and confirmed the accurate targeting of the lesion. Postdrug delivery, positron emission tomography-computed tomography (PET-CT) was obtained to confirm the distribution of the Y-90 particles. The technical success, median follow-up, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were recorded.

Results

A total of 56 hepatocellular carcinoma patients underwent TARE during this period, out of which 36 patients (30 males and 6 females) underwent Y90 TARE. The aetiology of cirrhosis included non-alcoholic steatohepatitis (NASH) (11), hepatitis C (HCV) (11), hepatitis B (HBV) (9), metabolic dysfunction and alcohol-associated liver disease (MetALD) (2), alcoholic liver disease (ALD) (1), cryptogenic (1), and autoimmune hepatitis (AIH) (1). The technical success was 100 % and the median follow-up was 7 months (range: 1-32 months). The median OS was 15 months (range 10.73-19.27 months; 95 % CI) and the median local PFS was 4 months (range 3.03-4.97 months; 95 % CI). The ORR (best response, CR + PR) was 58 %. No major complications were seen in this study.

Conclusion

TARE is a viable option for liver cancer in all stages, but more so in the advanced stages. The use of angio-CT in TARE aids in the precise delivery of the particles to the tumour and avoids non-target embolisation.

New insights into mechanisms and interventions of locoregional therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is responsible for a significant number of cancer-related deaths worldwide and its incidence is increasing. Locoregional treatments, which are precision procedures guided by imaging to specifically target liver tumors, play a critical role in the management of a substantial portion of HCC cases. These therapies have become an essential element of the HCC treatment landscape, with transarterial chemoembolization (TACE) being the treatment of choice for patients with intermediate to advanced stages of the disease. Other locoregional therapies, like radiofrequency ablation, are highly effective for small, early-stage HCC. Nevertheless, the advent of targeted immunotherapy has challenged these established treatments. Tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs) have shown remarkable efficacy in clinical settings. However, their specific uses and the development of resistance in subsequent treatments have led clinicians to reevaluate the future direction of HCC therapy. This review concentrates on the distinct features of both systemic and novel locoregional therapies. We investigate their effects on the tumor microenvironment at the molecular level and discuss how targeted immunotherapy can be effectively integrated with locoregional therapies. We also examine research findings from retrospective studies and randomized controlled trials on various combined treatment regimens, assessing their validity to determine the future evolution of locoregional therapies within the framework of personalized, comprehensive treatment.

The Influence of Additional Treatments on the Survival of Patients Undergoing Transarterial Radioembolization (TARE)

The aim of this study was to present our preliminary experience with transarterial radioembolization (TARE) using Yttrium-90 (90Y), compare the cancer-specific survival (CSS) of patients with hepatocellular carcinoma (HCC) and colorectal cancer (CRC) liver metastases undergoing TARE, and investigate the influence of additional treatments on CSS. Our database was interrogated to retrieve patients who had undergone TARE using Yttrium-90 (90Y) glass or resin microspheres. Kaplan-Meier curves and the log-rank test were employed to conduct survival analysis for the different groups (p < 0.05). Thirty-nine patients were retrieved (sex: 27 M, 12 F; mean age: 63.59 ± 15.66 years): twenty-three with hepatocellular carcinoma (HCC) and sixteen with CRC liver metastasis. Globally, the patients with HCC demonstrated a significantly longer CSS than those with CRC liver metastasis (22.64 ± 2.7 vs. 7.21 ± 1.65 months; p = 0.014). Among the patients with CRC liver metastasis, those receiving TARE and additional concomitant treatments (n = 10) demonstrated a longer CSS than the CRC patients receiving only TARE (9.97 ± 2.21 vs. 2.59 ± 0.24 months; p = 0.06). In the HCC group, there was a trend of a longer CSS in patients (n = 8) receiving TARE and additional treatments (27.89 ± 3.1 vs. 17.69 ± 3.14 months; p = 0.15). Patients with HCC seem to achieve a longer survival after TARE compared to patients with CRC liver metastases. In patients with CRC liver metastases, the combination of TARE and additional concomitant treatments may improve survival.

MIRD Pamphlet No. 29: MIRDy90-A 90Y Research Microsphere Dosimetry Tool

90Y-microsphere radioembolization has become a well-established treatment option for liver malignancies and is one of the first U.S. Food and Drug Administration-approved unsealed radionuclide brachytherapy devices to incorporate dosimetry-based treatment planning. Several different mathematical models are used to calculate the patient-specific prescribed activity of 90Y, namely, body surface area (SIR-Spheres only), MIRD single compartment, and MIRD dual compartment (partition). Under the auspices of the MIRDsoft initiative to develop community dosimetry software and tools, the body surface area, MIRD single-compartment, MIRD dual-compartment, and MIRD multicompartment models have been integrated into a MIRDy90 software worksheet. The worksheet was built in MS Excel to estimate and compare prescribed activities calculated via these respective models. The MIRDy90 software was validated against available tools for calculating 90Y prescribed activity. The results of MIRDy90 calculations were compared with those obtained from vendor and community-developed tools, and the calculations agreed well. The MIRDy90 worksheet was developed to provide a vetted tool to better evaluate patient-specific prescribed activities calculated via different models, as well as model influences with respect to varying input parameters. MIRDy90 allows users to interact and visualize the results of various parameter combinations. Variables, equations, and calculations are described in the MIRDy90 documentation and articulated in the MIRDy90 worksheet. The worksheet is distributed as a free tool to build expertise within the medical physics community and create a vetted standard for model and variable management.

Radiation Segmentectomy for the Treatment of Hepatocellular Carcinoma: A Practical Review of Evidence

Radiation segmentectomy is a versatile, safe, and effective ablative therapy for early-stage hepatocellular carcinoma. Advances in radiation segmentectomy patient selection, procedural technique, and dosimetry have positioned this modality as a curative-intent and guideline-supported treatment for patients with solitary HCC. This review describes key radiation segmentectomy concepts and summarizes the existing literary knowledgebase.

Interventional Radiology Locoregional Therapies for Intrahepatic Cholangiocarcinoma

Surgical resection remains the cornerstone of curative treatment for intrahepatic cholangiocarcinoma (iCCA), but this option is only available to a small percentage of patients. For patients with unresectable iCCA, systemic therapy with gemcitabine and platinum-based agents represents the mainstay of treatment; however, the armamentarium has grown to include targeted molecular therapies (e.g., FGFR2 inhibitors), use of adjuvant therapy, liver transplantation in select cases, immunotherapy, and locoregional liver-directed therapies. Despite advances, iCCA remains a challenge due to the advanced stage of many patients at diagnosis. Furthermore, given the improving options for systemic therapy and the fact that the majority of iCCA patients succumb to disease progression in the liver, the role of locoregional therapies has increased. This review will focus on the expanding role of interventional radiology and liver-directed therapies in the treatment of iCCA.

Radiation Major Hepatectomy Using Ablative Dose Yttrium-90 Radioembolization in Patients with Hepatocellular Carcinoma 5 cm or Larger

PURPOSE

To evaluate the safety and effectiveness of ablative radioembolization for large hepatocellular carcinoma (HCC) while preserving a small future liver remnant (FLR).

MATERIALS AND METHODS

Twenty-five patients with large HCC of ≥5 cm requiring treatment for >60% of the total liver volume and having well-preserved liver function were treated with ablative glass microsphere radioembolization at a single institution from January 2017 to December 2021. Radioembolization was performed with a mean absorbed dose of >150 Gy, and the FLR per nontumor liver volume (NTLV) was set at >30%. Changes in liver function, adverse events, duration of response (DoR) in a treated area, time-to-progression (TTP), and overall survival (OS) were retrospectively investigated.

RESULTS

The largest tumor diameter and planned dose per treated volume were 11.4 cm ± 3.9 and 242.3 Gy ± 63.6 (169.4 Gy ± 45.9 per whole liver volume), respectively. All patients remained at Child-Pugh Class A for 90 days. No patient experienced Grade 3‒4 hyperbilirubinemia or new ascites. One patient (lung dose, 27.8 Gy) developed radiation pneumonitis requiring transient steroid treatment. According to the posttreatment dosimetry, the tumorous and nontumorous liver absorbed doses were 418.8 Gy ± 227.4 and 69.0 Gy ± 32.1, respectively. The median DoR in a treated area and TTP were 22.0 and 17.1 months, respectively. The 5-year OS rate was 83.2%.

CONCLUSIONS

Ablative radioembolization of large HCC of ≥5 cm can be performed safely and effectively in patients with preserved liver function when FLR/NTLV exceeds 30%.

Anatomical Quantitative Volumetric Evaluation of Liver Segments in Hepatocellular Carcinoma Patients Treated with Selective Internal Radiation Therapy: Key Parameters Influencing Untreated Liver Hypertrophy

Background: Factors affecting morphological changes in the liver following selective internal radiation therapy (SIRT) are unclear, and the available literature focuses on non-anatomical volumetric assessment techniques in a lobar treatment setting. This study aimed to investigate quantitative changes in the liver post-SIRT using an anatomical volumetric approach in hepatocellular carcinoma (HCC) patients with different levels of treatment selectivity and evaluate the parameters affecting those changes. This retrospective, single-institution, IRB-approved study included 88 HCC patients. Whole liver, liver segments, tumor burden, and spleen volumes were quantified on MRI at baseline and 3/6/12 months post-SIRT using a segmentation-based 3D software relying on liver vascular anatomy. Treatment characteristics, longitudinal clinical/laboratory, and imaging data were analyzed. The Student's t-test and Wilcoxon test evaluated volumetric parameters evolution. Spearman correlation was used to assess the association between variables. Uni/multivariate analyses investigated factors influencing untreated liver volume (uLV) increase. Results: Most patients were cirrhotic (92%) men (86%) with Child-Pugh A (84%). Absolute and relative uLV kept increasing at 3/6/12 months post-SIRT vs. baseline (all, p ≤ 0.005) and was maximal during the first 6 months. Absolute uLV increase was greater in Child-Pugh A5/A6 vs. ≥B7 at 3 months (A5, p = 0.004; A6, p = 0.007) and 6 months (A5, p = 0.072; A6, p = 0.031) vs. baseline. When the Child-Pugh class worsened at 3 or 6 months post-SIRT, uLV did not change significantly, whereas it increased at 3/6/12 months vs. baseline (all p ≤ 0.015) when liver function remained stable. The Child-Pugh score was inversely correlated with absolute and relative uLV increase at 3 months (rho = -0.21, p = 0.047; rho = -0.229, p = 0.048). In multivariate analysis, uLV increase was influenced at 3 months by younger age (p = 0.013), administered 90Y activity (p = 0.003), and baseline spleen volume (p = 0.023). At 6 months, uLV increase was impacted by younger age (p = 0.006), whereas treatment with glass microspheres (vs. resin) demonstrated a clear trend towards better hypertrophy (f = 3.833, p = 0.058). The amount (percentage) of treated liver strongly impacted the relative uLV increase at 3/6/12 months (all f ≥ 8.407, p ≤ 0.01). Conclusion: Liver function (preserved baseline and stable post-SIRT) favored uLV hypertrophy. Younger patients, smaller baseline spleen volume, higher administered 90Y activity, and a larger amount of treated liver were associated with a higher degree of untreated liver hypertrophy. These factors should be considered in surgical candidates undergoing neoadjuvant SIRT.

The contest between internal and external-beam dosimetry: The Zeno's paradox of Achilles and the tortoise

Radionuclide therapy, also called molecular radiotherapy (MRT), has come of age, with several novel radiopharmaceuticals being approved for clinical use or under development in the last decade. External beam radiotherapy (EBRT) is a well-established treatment modality, with about half of all oncologic patients expected to receive at least one external radiation treatment over their disease course. The efficacy and the toxicity of both types of treatment rely on the interaction of radiation with biological tissues. Dosimetry played a fundamental role in the scientific and technological evolution of EBRT, and absorbed doses to the target and to the organs at risk are calculated on a routine basis. In contrast, in MRT the usefulness of internal dosimetry has long been questioned, and a structured path to include absorbed dose calculation is missing. However, following a similar route of development as EBRT, MRT treatments could probably be optimized in a significant proportion of patients, likely based on dosimetry and radiobiology. In the present paper we describe the differences and the similarities between internal and external-beam dosimetry in the context of radiation treatments, and we retrace the main stages of their development over the last decades.