Correlation of Y90-absorbed radiation dose to pathological necrosis in hepatocellular carcinoma: confirmatory multicenter analysis in 45 explants

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.

Radioembolization for Hepatocellular Carcinoma: a Comparison on Dual-phase Cone-beam CT, Contrast-enhanced CT (CECT) and 99mTc-macroaggregated albumin-SPECT/CT in predicting final distribution volumes and dosimetry of the post-embolization 90Y PET/CT

PURPOSE

Personalized treatment schemes are being systematically applied to ensure best treatment outcome in oncologic patients. This is true also for personalized dosimetry in transarterial radioembolization (TARE) in hepatocellular carcinoma (HCC) patients. Precise and detailed volumetric and functional data derived from radiological and nuclear imaging methods are essential for personalized dosimetry. We sought to evaluate accuracy of dual-phase cone-beam CT (CBCT) in comparison to pre-treatment contrast-enhanced CT (CECT), and 99mTc-macroaggregated albumin-SPECT/CT ([99mTc]MAA SPECT/CT) to predict and assess the efficacy of TARE based on post-treatment 90Y PET/CT.

MATERIAL AND METHODS

Thirty consecutive patients with HCC treated with TARE were included. Intraprocedural dual-phase CBCT acquisition protocol was developed to distinguish tumor volume in the early arterial phase and perfused volume of non-affected liver in the late arterial phase. Volumetric data obtained from pre-treatment CECT, dual-phase CBCT and [99mTc]MAA SPECT/CT were compared to post-treatment 90Y PET/CT considered the standard reference. Treatment simulations for final calculated dose from the different imaging derived volumes were then compared to post-treatment 90Y PET/CT.

RESULTS

CBCT resulted as the most accurate method in predicting tumor- (R2 0.88) and perfused volumes (R2 0.82). Dosimetry prediction planning performed on derived volumes from the different methods did not show significant difference (p < 0.05), yet highest concordance with 90Y PET/CT data was observed with dual-phase CBCT.

CONCLUSION

Our study shows that dual-phase CBCT acquisition is a novel alternative method for correctly and safely administering more accurate and defined doses during TARE.

CLINICALTRIALS

gov ID: NCT03981497.

Radiation Segmentectomy and Modified Radiation Lobectomy for Unresectable Early-Stage Intrahepatic Cholangiocarcinoma

PURPOSE

To validate the safety and effectiveness of radiation segmentectomy (RS) and modified radiation lobectomy (mRL) in intrahepatic cholangiocarcinoma (iCCA) and to evaluate long-term outcomes in patients with unresectable, early-stage iCCA.

MATERIALS AND METHODS

A single-institution, retrospective study of patients with unresectable, solitary iCCA without extrahepatic disease or vascular involvement (Stage I) treated with RS and mRL was performed. Fifteen patients met inclusion criteria (median age, 65.5 years), including 11 (73%) with T1a disease and 4 (27%) with T1b disease. Outcomes included biochemical and clinical toxicities, tumor response by Response Evaluation Criteria in Solid Tumors (RECIST), time to progression, and overall survival (OS).

RESULTS

Median treatment dose was 308.2 Gy (range, 194.2-879.3 Gy). There were no cases of periprocedural mortality or hepatic deterioration. Grade 3+ clinical toxicities occurred in 1 patient (7%). The 3-month and best objective response rates by RECIST were 47% and 60%, respectively. Three patients went on to surgery with explant pathology revealing complete pathologic necrosis. Target lesion progression occurred in 4 patients at a median of 43.4 months. Median OS was 72 months. The 1-, 3-, and 5-year OS rates were 100%, 73.3%, and 50.3%, respectively.

CONCLUSIONS

RS and mRL were safe and effective in treating unresectable, early-stage iCCA. Overall progression of 47% and 5-year OS of 50% were comparable with those of surgical resection. RS and mRL may represent viable therapeutic options for patients with early-stage disease deemed surgically unresectable.

The Impact of Radiation Dose and Tumour Burden on Outcomes in Hepatocellular Carcinoma: 11-Year Experience in a 413-Patient Cohort Treated with Yttrium-90 Resin Microsphere Radioembolisation

Introduction

Transarterial radioembolisation (RE) using yttrium-90 (Y-90) microspheres is a widely used locoregional therapy for a broad spectrum of hepatocellular carcinoma (HCC) given its favourable safety profile. We evaluated the real-world outcomes of unresectable HCC treated with resin Y-90 RE and the relationship between tumour absorbed dose and subsequent curative therapy with survival.

Methods

Included were consecutive patients treated with Y-90 resin microspheres RE for unresectable HCC between January 2008 and May 2019 at the National Cancer Centre Singapore/Singapore General Hospital. The outcomes were stratified by tumour burden, distribution, presence of portal vein invasion (PVI) and liver function to improve prognostication.

Results

The median overall survival (OS) evaluated on 413 included patients was 20.9 months (95% CI: 18.2-24.0). More than half of the patients (214/413, 51.8%) had HCC beyond up-to-seven criteria, and 37.3% had portal vein invasion (154/413, 37.3%). Majority (71.7%) had dosimetry calculated based on the partition model. Patients who received ≥150 Gy to tumour had significantly better outcomes (OS 32.2 months, 95% CI: 18.3-46.4) than those who did not (OS 17.5 months, 95% CI: 13.7-22.7, p < 0.001). Seventy patients (17%) received curative therapies after tumour was downstaged by Y-90 RE and had better OS of 79.7 months (95% CI: 40.4 - NE) compared to those who did not receive curative therapies (OS 17.1 months; 95% CI: 13.5-20.4, p < 0.001). RE-induced liver injury was observed in 5.08% of the patients while 3.2% of the patients had possible radiation pneumonitis but none developed Grade 3-4 toxicity. For HCC without PVI, OS differed significantly with performance status, albumin-bilirubin grade, tumour distribution, and radiation dose; for HCC with PVI, Child-Pugh class and AFP were significant predictors of survival.

Conclusions

Treatment outcomes for unresectable HCC using Y-90 RE were favourable. Incorporating tumour burden and distribution improved prognostication. Patients who received tumour absorbed dose above 150 Gy had better OS. Patients who subsequently received curative therapies after being downstaged by Y-90 RE had remarkable clinical outcomes.

Advances in radiation therapy for HCC: Integration with liver-directed treatments

HCC is the fourth leading cause of cancer-related mortality with increasing incidence worldwide. Historically, treatment for early disease includes liver transplantation, surgical resection, and/or other local therapies, such as thermal ablation. As a result of technical advances and high-quality prospective data, the use of definitive external beam radiotherapy with ablative doses has emerged. Intermediate-stage disease has been generally addressed with arterially directed therapies (eg, chemoembolization or radioembolization) and external beam radiotherapy, while advanced stages have been addressed by systemic therapy or best supportive care. The role of each local/locoregional therapy has rapidly evolved in the context of novel pharmacotherapies, including immunotherapies and antiangiogenic agents. The combinations, indications, and timing of treatments vary widely among specialties and geographies. Here, we aim to synthesize the best quality evidence available regarding the efficacy and safety of different liver-directed modalities, with a focus on recent prospective clinical data of external beam radiotherapy within the context of other available liver-directed therapies across Barcelona Liver Classification (BCLC) stages.

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.

Usefulness of multiphasic MRI in assessing suitability for SIRT in treatment of liver malignancies

AIM

To evaluate the predictive value of multiphasic magnetic resonance imaging (MRI) in identifying liver tumor perfusion characteristics and to compare it with hepatic artery perfusion scintigraphy findings in patients considered for selective internal radiation therapy (SIRT) with yttrium-90 (Y-90).

METHODS

This study included 93 patients diagnosed with primary or secondary liver cancer between May 2021 and February 2024, comprising 47 patients (27 M/20F) deemed unsuitable for SIRT and 46 patients (26 M/20F) eligible for SIRT. The relationship between multiphasic MRI and scintigraphy findings in determining perfusion of tumors was analyzed. Predictive performance was evaluated with receiver operating characteristic (ROC) analysis, and the optimal cut-off values were determined using the Youden index.

RESULTS

The SIRT unsuitable group had a lower frequency of intratumoral arterial phase hyperenhancement(APHE) (40.43% vs. 69.57%, p = 0.042), presence of hyperintensity on T2 sequence (72.34% vs. 95.65%, p = 0.026), lower lesion intensity in the portal phase (p = 0.033), and a lower lesion-to-liver intensity ratio in the portal phase (≤ 0.97, p = 0.011). The absence of intratumoral APHE [p = 0.049, AUC (95% CI) = 0.646 (0.508-0.783)] and a lesion-to-liver intensity ratio in the portal phase with a cut-off value of ≤ 0.97 [p = 0.011, AUC (95% CI) = 0.689 (0.564-0.815)] were significant predictors of SIRT unsuitability.

CONCLUSION

Both the absence of intratumoral APHE and a lower lesion-to-liver intensity ratio in the portal phase were significant predictors of SIRT unsuitability.

Resin-Based Yttrium-90 Radioembolization as a Bridging or Downstaging Treatment to Liver Transplantation for Hepatocellular Carcinoma

PURPOSE

To evaluate the outcomes of resin-based yttrium-90 (90Y) transarterial radioembolization (TARE) for hepatocellular carcinoma (HCC) as a bridging or downstaging therapy to liver transplantation (LT) in terms of safety, tumor response, recurrence, and survival.

MATERIALS AND METHODS

A single-center retrospective analysis of patients with HCC treated with resin-based TARE as bridging or downstaging treatment to LT between January 2006 and April 2021 was performed. TARE-related liver toxicity was assessed. Imaging data were analyzed to assess tumor response. Histopathological analysis of explant livers was performed to assess HCC necrosis. Survival and bridging/downstaging success predictor analysis was performed.

RESULTS

Thirty-six patients underwent resin-based TARE with the intention to bridge (33%) or downstage (67%) to LT. Overall, 44% had ≥3 HCC lesions, and 53% had bilobar disease. Median largest tumor diameter was 3.4 cm. TARE was segmental, lobar, and bilobar in 20%, 36%, and 44% of cases, respectively. In total, 17% had Grade 3 bilirubin toxicities. The objective response rate per modified Response Evaluation Criteria in Solid Tumours was 72%. Patients meeting the United Network for Organ Sharing Downstaging criteria had higher chances of successful bridging/downstaging. Twenty-three patients were transplanted. Complete pathological response was noted in 30% of explant livers. Posttransplant tumor recurrence occurred in 26% within a median follow-up period of 1,710 days. Estimated 5-year progression-free, disease-specific, and overall survival rates after LT were 89%, 69%, and 89%, respectively. For the entire patient cohort, these survival rates were 87%, 53%, and 70%, respectively.

CONCLUSIONS

Resin-based 90Y TARE can be considered a valuable treatment option for bridging or downstaging patients with HCC to LT, including patients requiring lobar or bilobar TARE for extensive tumoral disease.

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.

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.

The role of biomarkers and dosimetry parameters in overall and progression free survival prediction for patients treated with personalized 90Y glass microspheres SIRT: a preliminary machine learning study

BACKGROUND

Overall Survival (OS) and Progression-Free Survival (PFS) analyses are crucial metrics for evaluating the efficacy and impact of treatment. This study evaluated the role of clinical biomarkers and dosimetry parameters on survival outcomes of patients undergoing 90Y selective internal radiation therapy (SIRT).

MATERIALS/METHODS

This preliminary and retrospective analysis included 17 patients with hepatocellular carcinoma (HCC) treated with 90Y SIRT. The patients underwent personalized treatment planning and voxel-wise dosimetry. After the procedure, the OS and PFS were evaluated. Three structures were delineated including tumoral liver (TL), normal perfused liver (NPL), and whole normal liver (WNL). 289 dose-volume constraints (DVCs) were extracted from dose-volume histograms of physical and biological effective dose (BED) maps calculated on 99mTc-MAA and 90Y SPECT/CT images. Subsequently, the DVCs and 16 clinical biomarkers were used as features for univariate and multivariate analysis. Cox proportional hazard ratio (HR) was employed for univariate analysis. HR and the concordance index (C-Index) were calculated for each feature. Using eight different strategies, a cross-combination of various models and feature selection (FS) methods was applied for multivariate analysis. The performance of each model was assessed using an averaged C-Index on a three-fold nested cross-validation framework. The Kaplan-Meier (KM) curve was employed for univariate and machine learning (ML) model performance assessment.

RESULTS

The median OS was 11 months [95% CI: 8.5, 13.09], whereas the PFS was seven months [95% CI: 5.6, 10.98]. Univariate analysis demonstrated the presence of Ascites (HR: 9.2[1.8,47]) and the aim of SIRT (segmentectomy, lobectomy, palliative) (HR: 0.066 [0.0057, 0.78]), Aspartate aminotransferase (AST) level (HR:0.1 [0.012-0.86]), and MAA-Dose-V205(%)-TL (HR:8.5[1,72]) as predictors for OS. 90Y-derived parameters were associated with PFS but not with OS. MAA-Dose-V205(%)-WNL, MAA-BED-V400(%)-WNL with (HR:13 [1.5-120]) and 90Y-Dose-mean-TL, 90Y-D50-TL-Gy, 90Y-Dose-V205(%)-TL, 90Y-Dose- D50-TL-Gy, and 90Y-BED-V400(%)-TL (HR:15 [1.8-120]) were highly associated with PFS among dosimetry parameters. The highest C-index observed in multivariate analysis using ML was 0.94 ± 0.13 obtained from Variable Hunting-variable-importance (VH.VIMP) FS and Cox Proportional Hazard model predicting OS, using clinical features. However, the combination of VH. VIMP FS method with a Generalized Linear Model Network model predicting OS using Therapy strategy features outperformed the other models in terms of both C-index and stratification of KM curves (C-Index: 0.93 ± 0.14 and log-rank p-value of 0.023 for KM curve stratification).

CONCLUSION

This preliminary study confirmed the role played by baseline clinical biomarkers and dosimetry parameters in predicting the treatment outcome, paving the way for the establishment of a dose-effect relationship. In addition, the feasibility of using ML along with these features was demonstrated as a helpful tool in the clinical management of patients, both prior to and following 90Y-SIRT.

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.

Voxel-based tumor dose correlates to complete pathologic necrosis after transarterial radioembolization for hepatocellular carcinoma

PURPOSE

The transarterial radioembolization (TARE) dose is traditionally calculated using the single-compartment Medical Internal Radiation Dose (MIRD) formula. This study utilized voxel-based dosimetry to correlate tumor dose with explant pathology in order to identify dose thresholds that predicted response.

METHODS

All patients with HCC treated with TARE using yttrium-90 [90Y] glass microspheres at a single institution between January 2015 - June 2023 who underwent liver transplantation were eligible. The [90Y] distribution and dose-volume histograms were determined using Simplicity90 (Mirada Medical, Oxford UK) with a Bremsstrahlung SPECT/CT. A complete response was assigned if explant pathology showed complete necrosis and the patient had not undergone additional treatments to the same tumor after TARE. Logistic regression and receiver operator characteristic (ROC) curves were constructed to evaluate dose thresholds correlated with response.

RESULTS

Forty-one patients were included. Twenty-six (63%) met criteria for complete response. Dose to 95% (D95), 70% (D70), and 50% (D50) of the tumor volume were associated with likelihood of complete response by logistic regression (all p < 0.05). For lesions with complete response versus without, the median D95 was 813 versus 232 Gy, D70 was 1052 versus 315 Gy, and D50 was 1181 versus 369 Gy (all p < 0.01). A D95 > 719 Gy had the highest accuracy at 68% (58% sensitivity, 87% specificity) for predicting complete response. Median percent of tumor volume receiving at least 100 Gy (V100), 200 Gy (V200), 300 Gy (V300), and 400 Gy (V400) also differed by pathologic response: the median V100, V200, V300, and V400 was 100% versus 99%, 100% versus 97%, 100% versus 74%, and 100% versus 43% in the complete response versus non-complete response groups, respectively (all p < 0.05).

CONCLUSION

Voxel-based dosimetry was well-correlated with explant pathology. The D95 threshold had the highest accuracy, suggesting the D95 may be a relevant target for multi-compartment dosimetry.

Resin-Based 90 Y Tumor Dose as a Predictor of Duration of Response and Survival in Patients With Surgically Unresectable Hepatocellular Carcinoma : A Prospective Single-Arm Study

BACKGROUND

Personalized dosimetry improves overall survival (OS) in patients with hepatocellular carcinoma (HCC) treated with glass 90 Y radioembolization. This study evaluated personalized tumor dose (TD) as a predictor of OS, progression-free survival (PFS), and local duration of response (DOR) in patients with surgically unresectable HCC treated with resin 90 Y radioembolization.

PATIENTS AND METHODS

This prospective, single-center, single-arm clinical trial (NCT04172714) evaluated the efficacy of scout activity of resin 90 Y versus 99m Tc-MAA for treatment planning. A secondary aim of this study was to evaluate personalized dosimetry as a predictor of OS, PFS, and DOR. Partition dosimetry model was utilized for nonsegmental therapies with targeted TD >200 Gy and nontumoral liver dose <70 Gy. Single compartment dose of 200 Gy was used for segmentectomies. OS, PFS, and local DOR from 90 Y was estimated using Kaplan-Meier estimation with log-rank analysis used to determine predictors of prolonged survival.

FINDINGS

Thirty patients with treatment-naive HCC and 33 tumors (19 segmental and 14 nonsegmental) were included. Overall, 18 patients underwent segmental Y90-RE and 12 underwent non-segmental/lobar therapies. The mean 90 Y TD was 493 Gy. The median follow-up since enrollment into the study was 37 months. The mean OS was 32.2 months for the entire cohort. A total of 5 patients underwent orthotopic liver transplantation post 90 Y and were excluded from further survival analysis. The mean OS for the remainder of the cohort was 30.1 months (median not reached). The mean TD >250 Gy resulted in prolonged mean OS and PFS. The median local DOR was 32.7 months with mean TD 330 Gy predicting prolonged DOR.

INTERPRETATION

For patients with surgically unresectable HCC treated with resin 90 Y, there is mean TD threshold predicting prolonged OS, PFS, and local DOR. Therefore, there should be further emphasis on personalized dosimetry for optimization of patient outcomes.

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.

Selective internal radiation therapy segmentectomy: A new minimally invasive curative option for primary liver malignancies?

Transarterial radioembolization or selective internal radiation therapy (SIRT) has emerged as a minimally invasive approach for the treatment of tumors. This percutaneous technique involves the local, intra-arterial delivery of radioactive microspheres directly into the tumor. Historically employed as a palliative measure for liver malignancies, SIRT has gained traction over the past decade as a potential curative option, mirroring the increasing role of radiation segmentectomy. The latest update of the BCLC hepatocellular carcinoma guidelines recognizes SIRT as an effective treatment modality comparable to other local ablative methods, particularly well-suited for patients where surgical resection or ablation is not feasible. Radiation segmentectomy is a more selective approach, aiming to deliver high-dose radiation to one to three specific hepatic segments, while minimizing damage to surrounding healthy tissue. Future research efforts in radiation segmentectomy should prioritize optimizing radiation dosimetry and refining the technique for super-selective administration of radiospheres within the designated hepatic segments.

Local recurrence following a complete radiologic response in hepatocellular carcinoma patients: comparison of transarterial chemoembolisation and transarterial radioembolisation

AIM

To evaluate and compare the rates of local recurrence in hepatocellular carcinoma (HCC) patients who undergo selective transarterial radioembolisation (TARE) or transarterial chemoembolisation (TACE) and achieve a complete response (CR) radiologically.

MATERIALS AND METHODS

All patients undergoing treatment with TARE or TACE at a single academic institution were reviewed retrospectively. Those who had been treated previously, presented with multifocal disease, had non-selective TARE or TACE, or did not achieve a complete response (CR) radiologically were excluded.

RESULTS

In total 110 patients were included (TACE n=60 [54.5%]; TARE n=50 [45.5%]). TARE patients were older (66.4 ± 9.4 versus 61.2 ± 5.6 years, p<0.001) and had larger tumours (4.4 ± 2.2 versus 3 ± 1.4 cm, p=0.002). TACE patients were significantly more likely to suffer a local recurrence (31/60, 51.7% versus 9/50, 18%, p<0.001) and had a significantly shorter time to recurrence (median 8.3 {interquartile range [IQR]}: 12 versus median 17.9 [IQR: 23.5] months, p=0.001). A local time to progression (TTP) Kaplan-Meier curve demonstrated TACE patients had a significantly shorter local TTP (hazard ratio [HR]: 7.2; 95% confidence interval [CI]: 3.64-14.24; p<0.001) and treatment modality (TACE or TARE; HR: 0.05; 95% CI: 0.005-0.5; p=0.01) was found to be associated with local recurrences on multivariate Cox proportional HR analysis. When overall TTP was evaluated, again TACE patients were found to have a significantly shorter TTP (HR: 2.13 [1.28-3.53], p=0.004).

CONCLUSION

In HCC patients undergoing selective treatment who achieve a CR radiologically, those treated with TARE may be less likely to suffer recurrence, either local or general, than those treated with TACE.

Long-term Clinical Outcomes of Yttrium-90 Transarterial Radioembolization for Hepatocellular Carcinoma: A 5-Year Institutional Experience

RATIONALE AND OBJECTIVES

To examine the clinical outcomes of yttrium-90 (Y90) transarterial radioembolization (TARE) for primary hepatocellular carcinoma (HCC) through the evaluation of a 5-year institutional experience.

MATERIALS AND METHODS

This retrospective study evaluated 88 consecutive patients with primary HCC receiving Y90 TARE treatment at an academic medical center from 2017 to 2021. Disease distribution was bilobar in 60.2% of patients with an average lesion diameter of 5.0 ± 3.4 cm and Barcelona Clinic Liver Cancer stage B or C in 77% of the participants. Clinical outcomes were elucidated by examination of complications, liver function tests, biochemical response, and radiographic response. Objective response ratio (ORR) and progression-free survival (PFS) were also calculated.

RESULTS

The mean administered Y90 radiation dose was 127.8 ± 20.2 Gy. No significant complications or LFT elevations occurred post-therapy. Of the 73.9% of patients with α-fetoprotein-producing tumors, 67.8% experienced a complete or partial biochemical response 1 month post-treatment. The ORR was 83.3% on 6-month imaging and PFS was 9.6 ± 8.5 months. Functional outcomes (Eastern Cooperative Oncology Group) were maintained or improved in 79.6% and 76.1% of patients by 6 months and 1 year post-treatment, respectively. The mean survival was 14.7 ± 12.1 months. At 6 months post-treatment, 77.3% of patients were downstaged to or maintained Milan criteria, which was sustained for 74.4% and 70.0% of patients 1 year and 2 years after treatment, respectively.

CONCLUSION

Y90-TARE is a safe and effective therapy for primary HCC. Enduring outcomes further act as a realistic bridge to liver transplantation, with a majority of patients maintaining Milan criteria and preserving their functional status long term.

Efficacy and Safety of Radiation Segmentectomy with 90Y Resin Microspheres for Hepatocellular Carcinoma

Background Limited data are available on radiation segmentectomy (RS) for treatment of hepatocellular carcinoma (HCC) using yttrium 90 (90Y) resin microsphere doses determined by using a single-compartment medical internal radiation dosimetry (MIRD) model. Purpose To evaluate the efficacy and safety of RS treatment of HCC with 90Y resin microspheres using a single-compartment MIRD model and correlate posttreatment dose with outcomes. Materials and Methods This retrospective single-center study included adult patients with HCC who underwent RS with 90Y resin microspheres between July 2014 and December 2022. Posttreatment PET/CT and dosimetry were performed. Adverse events were assessed using the Common Terminology Criteria for Adverse Events, version 5.0. Per-lesion and overall response rates (ie, complete response [CR], objective response, disease control, and duration of response) were assessed at imaging using the Modified Response Evaluation Criteria in Solid Tumors, and overall survival (OS) was assessed using Kaplan-Meier analysis. Results Among 67 patients (median age, 69 years [IQR, 63-78 years]; 54 male patients) with HCC, median tumor absorbed dose was 232 Gy (IQR, 163-405 Gy). At 3 months, per-lesion and overall (per-patient) CR was achieved in 47 (70%) and 41 (61%) of 67 patients, respectively. At 6 months (n = 46), per-lesion rates of objective response and disease control were both 94%, and per-patient rates were both 78%. A total of 88% (95% CI: 79 99) and 72% (95% CI: 58, 90) of patients had a per-lesion and overall duration of response of 1 year or greater. At 1 month, a grade 3 clinical adverse event (abdominal pain) occurred in one of 67 (1.5%) patients. Median posttreatment OS was 26 months (95% CI: 20, not reached). Disease progression at 2 years was lower in the group that received 300 Gy or more than in the group that received less than 300 Gy (17% vs 61%; P = .047), with no local progression in the former group through the end of follow-up. Conclusion Among patients with HCC who underwent RS with 90Y resin microspheres, 88% and 72% achieved a per-lesion and overall duration of response of 1 year or greater, respectively, with one grade 3 adverse event. In patients whose tumors received 300 Gy or more according to posttreatment dosimetry, a disease progression benefit was noted. © RSNA, 2024 Supplemental material is available for this article.

Locoregional Therapies for Hepatocellular Carcinoma prior to Liver Transplant: Comparative Pathologic Necrosis, Radiologic Response, and Recurrence

PURPOSE

To compare pathologic tumor necrosis rates after locoregional therapies (LRTs) for hepatocellular carcinoma (HCC) prior to liver transplantation and evaluate radiologic-pathologic correlation along with posttransplant HCC recurrence.

MATERIALS AND METHODS

Consecutive patients with solitary HCC bridged or downstaged with LRT from 2010 to 2022 were included. LRTs were transarterial chemoembolization (TACE), radioembolization (yttrium-90 [90Y]), ablation, and stereotactic body radiotherapy (SBRT). Upfront combination therapy options were TACE/ablation and TACE/SBRT. Subsequent therapy crossover due to local recurrence was allowed. Posttreatment imaging closest to the time of transplant, explant histopathologic necrosis, and tumor recurrence after transplant were reviewed.

RESULTS

Seventy-three patients met inclusion criteria, of whom 5 (7%) required downstaging. 90Y alone (n = 36) and multimodal therapy (pooled upfront combination and crossover therapy, n = 23) resulted in significantly greater pathologic necrosis compared with TACE alone (n = 14; P = .01). High dose 90Y radiation segmentectomy (≥190 Gy; n = 27) and TACE/ablation (n = 7) showed highest rates of complete pathologic necrosis (CPN)-63% (n = 17) and 71% (n = 5), respectively. Patients with CPN had a mean lesion size of 2.5 cm, compared with 3.2 cm without CPN (P = .04), irrespective of LRT modality. HCC recurrence was more common in patients without CPN (16%, 6/37) than in those with CPN (3%, 1/36; P = .11). Using Liver Imaging Reporting and Data System (LI-RADS), a nonviable imaging response was 75% sensitive and 57% specific for CPN.

CONCLUSIONS

Radiation segmentectomy and multimodal therapy significantly improved CPN rates compared with TACE alone. A LI-RADS treatment response of nonviable did not confidently predict CPN.

Tumor Size and Watershed Area Correlate with Incomplete Treatment and Tumor Progression after Selective Radioembolization for Hepatocellular Carcinoma

PURPOSE

To identify factors of incomplete treatment after segmental transarterial radioembolization (TARE) for treatment-naive and solitary hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A total of 75 consecutive patients (age, 68.5 years [SD ± 8.0]; 25/75 [33.3%] women) with treatment-naive, solitary HCC underwent segmental or subsegmental TARE with glass microspheres (tumor size, 3.8 cm [SD ± 2.2]; administered dose, 222.6 Gy [SD ± 123.9]) at a single institution from November 2015 to June 2022. Radiologic response and progression-free survival (PFS) were assessed as per modified Response Evaluation Criteria in Solid Tumors.

RESULTS

Complete treatment was achieved in 48 of 75 (64.0%) patients (mean follow-up, 33.2 months [SD ± 27.4]). Patients with incomplete treatment (27/75, 36%) presented with larger tumor size (5.0 [SD ± 2.5] vs 3.1 [SD ± 1.6] cm; P = .0001), with more tumors located in the watershed zone (81.5% vs 41.7%; P = .001). These patients were less likely to be bridged to transplant or resection (22.2% vs 52.1%; P = .015). Watershed tumors demonstrated worse target tumor PFS (median PFS, 19 months vs not reached; P = .0104) and overall PFS (9.1 months vs not reached; P = .0077). Watershed location was associated with worse PFS among tumors >3 cm in size (8.4 months vs not reached; P = .035) but not in tumors ≤3 cm in size (52.2 months vs not reached; P = .915).

CONCLUSIONS

Tumor size and watershed location were associated with incomplete treatment after segmental TARE for HCC. Watershed tumors were associated with worse PFS, particularly tumors larger than 3 cm. These tumors may require careful treatment planning and repeated treatments to ensure a durable response.

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.

Long-Term Overall Survival After Selective Internal Radiation Therapy for Locally Advanced Hepatocellular Carcinomas: Updated Analysis of DOSISPHERE-01 Trial

Interim analysis of the DOSISPHERE-01 study demonstrated a strong improvement in response and overall survival (OS) on using 90Y-loaded glass microspheres with personalized dosimetry compared with standard dosimetry in patients with nonoperable locally advanced hepatocellular carcinoma. This report sought to provide a long-term analysis of OS. Methods: In this phase II study (ClinicalTrials.gov identifier NCT02582034), treatment was randomly assigned (1:1) with the goal to deliver either at least 205 Gy (if possible >250-300 Gy) to the index lesion in the personalized dosimetry approach (PDA) or 120 ± 20 Gy to the treated volume in the standard dosimetry approach (SDA). The 3-mo response of the index lesion was the primary endpoint, with OS being one of the secondary endpoints. This report is a post hoc long-term analysis of OS. Results: Overall, 60 hepatocellular carcinoma patients with at least 1 lesion larger than 7 cm and more than 30% of hepatic reserve were randomized (intent-to-treat population: PDA, n = 31; SDA, n = 29), with 56 actually treated (modified intent-to-treat population: n = 28 in each arm). The median follow-up for long-term analysis was 65.8 mo (range, 2.1-73.1 mo). Median OS was 24.8 mo and 10.7 mo (hazard ratio [HR], 0.51; 95% CI, 0.29-0.9; P = 0.02) for PDA and SDA, respectively, in the modified intent-to-treat population. Median OS was 22.9 mo for patients with a tumor dose of at least 205 Gy, versus 10.3 mo for those with a tumor dose of less than 205 Gy (HR, 0.42; 95% CI, 0.22-0.81; P = 0.0095), and was 22.9 mo for patients with a perfused liver dose of 150 Gy or higher, versus 10.3 mo for those with a perfused liver dose of less than 150 Gy (HR, 0.42; 95% CI, 0.23-0.75; P = 0.0033). Lastly, median OS was not reached in patients who were secondarily resected (n = 11, 10 in the PDA group and 1 in the SDA group), versus 10.8 mo in those without secondary resection (n = 45) (HR, 0.17; 95% CI, 0.065-0.43; P = 0.0002). Only resected patients displayed favorable long-term OS rates, meaning an OS of more than 50% at 5 y. Conclusion: After longer follow-up, personalized dosimetry sustained a meaningful improvement in OS, which was dramatically improved for patients who were accurately downstaged toward resection, including most portal vein thrombosis patients.

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%.

Locoregional Therapies for Primary and Metastatic Breast Cancer: AJR Expert Panel Narrative Review

Minimally invasive locoregional therapies have a growing role in the multidisciplinary treatment of primary and metastatic breast cancer. Factors contributing to the expanding role of ablation for primary breast cancer include earlier diagnosis, when tumors are small, and increased longevity of patients whose condition precludes surgery. Cryoablation has emerged as the leading ablative modality for primary breast cancer owing to its wide availability, the lack of need for sedation, and the ability to monitor the ablation zone. Emerging evidence suggests that in patients with oligometastatic breast cancer, use of locoregional therapies to eradicate all disease sites may confer a survival advantage. Evidence also suggests that transarterial therapies-including chemoembolization, chemoperfusion, and radioembolization-may be helpful to some patients with advanced liver metastases from breast cancer, such as those with hepatic oligoprogression or those who cannot tolerate systemic therapy. However, the optimal modalities for treatment of oligometastatic and advanced metastatic disease remain unknown. Finally, locoregional therapies may produce tumor antigens that in combination with immunotherapy drive anti-tumor immunity. Although key trials are ongoing, additional prospective studies are needed to establish the inclusion of interventional oncology in societal breast cancer guidelines to support further clinical adoption and improved patient outcomes.

Clinical course of patients with hepatocellular carcinoma who experienced radiologic complete response after radioembolization

Purpose

The purpose of this study is to elucidate the patterns of recurrence of hepatocellular carcinoma and to analyze factors that can predict recurrence after complete response to radioembolization.

Materials and methods

A total of 289 consecutive patients who underwent radioembolization for the treatment of hepatocellular carcinoma at a single tertiary center were retrospectively reviewed. Baseline characteristics were collected and compared between the group showing complete response and the group showing noncomplete response. Data on recurrence status, time to recurrence, and the patterns of recurrence among the patients who showed radiologic complete response were collected. The group that maintained complete response and the group that experienced recurrence were compared, and the risk factors affecting recurrence were evaluated by logistic regression analysis.

Results

The complete response rate was 24.9% (73/289). Age, sex, tumor markers, maximum tumor diameter, multiplicity, presence of vascular invasion, and target radiation dose were significantly different between the complete response and noncomplete response groups. The recurrence rate after complete response was 38.4% (28/73), and 67.9% (19/28) of recurrences occurred by 8 months after complete response. Eight patients who underwent resection/transplantation after complete response experienced no recurrence. Multiple tumors and a lower target radiation dose were independent risk factors of recurrence after complete response in the multivariate logistic regression.

Conclusion

Hepatocellular carcinoma recurrence following complete response after radioembolization is not uncommon and frequently occurs within 1 year after complete response. Multiple tumors and a lower target radiation dose may be risk factors for recurrence.

Radiation Segmentectomy for Hepatocellular Carcinoma

The application of trans-arterial radioembolization (TARE) with Yttrium-90, historically a palliative treatment option for patients with advanced hepatocellular carcinoma (HCC), is evolving. Radiation segmentectomy (RADSEG), the segmental delivery of an ablative radiation dose, is a treatment option for patients with earlier-stage HCC. This review presents an in-depth exploration of RADSEG, emphasizing its technical considerations, dosimetry advancements, and patient selection. The integration of RADSEG into the Barcelona Clinic Liver Cancer (BCLC) paradigm will be highlighted. RADSEG outcomes concerning safety and efficacy will be explored and compared with traditional locoregional cancer treatments like trans-arterial chemoembolization (TACE), percutaneous thermal ablation, and surgical resection, with an eye on future directions and considerations.

Predictive Dosimetry and Outcomes of Hepatocellular Carcinoma Treated by Yttrium-90 Resin Microsphere Radioembolization: A Retrospective Analysis Using Technetium-99m Macroaggregated Albumin Single Photon Emission CT/CT and Planning Software

PURPOSE

To characterize estimated mean absorbed tumor dose (ADT), objective response (OR), and estimated target dose of hepatocellular carcinoma (HCC) after resin microsphere yttrium-90 (90Y) radioembolization using partition dosimetry.

MATERIALS AND METHODS

In this retrospective, single-center study, multicompartment dosimetry of index tumors receiving 90Y radioembolization between October 2015 and June 2022 was performed using a commercial software package and pretreatment technetium-99m macroaggregated albumin single photon emission computed tomography (SPECT)/computed tomography (CT). In total, 101 patients with HCC underwent 102 treatments of 127 index tumors. Patients underwent imaging every 2-3 months after treatment to determine best response per modified Response Evaluation Criteria in Solid Tumors (mRECIST). Best response was defined as the greatest response category per mRECIST and categorized as OR or nonresponse (NR). A Cox proportional hazards model evaluated the probability of tumor OR and progression-free survival using ADT.

RESULTS

The median follow-up period was 148 days (interquartile range [IQR], 92-273 days). The median ADT of OR was 141.9 Gy (IQR, 89.4-215.8 Gy) compared with the median ADT of NR treatments of 70.8 Gy (IQR, 42.0-135.3 Gy; P < .001). Only ADT was predictive of response (hazard ratio = 2.79 [95% confidence interval {CI}: 1.44-5.40]; P = .003). At 6 months, an ADT of 157 Gy predicted 90.0% (95% CI: 41.3%-98.3%) probability of OR. At 1 year, an ADT of 157 Gy predicted 91.6% (95% CI: 78.3%-100%) probability of progression-free survival. Partition modeling and delivered activity were predictive of progression (P = .021 and P = .003, respectively).

CONCLUSIONS

For HCC treated with resin microspheres, tumors receiving higher ADT exhibited higher rates of OR. An ADT of 157 Gy predicted 90.0% OR at 6 months.

Management of Intermediate-Stage Hepatocellular Carcinoma: Systemic Versus Locoregional Therapy

Intermediate-stage hepatocellular carcinoma (HCC) comprises a heterogeneous group of patients with varying levels of tumor burden. Transarterial chemoembolization was traditionally the mainstay of treatment for intermediate-stage HCC for almost 2 decades. New and emerging treatment options have revolutionized HCC therapy, allowing for broader application to patients with intermediate- and advanced-stage disease. Accordingly, new guidelines acknowledge these options, and intermediate stage HCC can now be treated with surgical, locoregional or systemic therapies, or a combination thereof. Patients will continue to benefit from the development of complex treatment strategies in a multidisciplinary setting to optimize individual outcomes.

Ablation versus Radiation Segmentectomy for Small Liver Tumors

Hepatocellular carcinoma (HCC) is a liver malignancy that affects more than a million people worldwide with a complex multifactorial etiology. After the diagnosis of HCC is made, physicians establish management using the Barcelona Clinic Liver Cancer (BCLC) guidelines revolving around tumor stage, liver function, performance status, and patient preferences. According to recent updates to these guidelines, thermal ablation is the second-best curative option apart from surgical resection for small HCC (< 2 cm). While thermal ablation is standard of care, recent studies have suggested that radiation segmentectomy (RS) has similar outcomes, limited hepatotoxicity, and ultimately a cost-efficient approach. Although there is limited literature on RS, this article compares ablation techniques against radiation segmentectomy for small HCC tumors.

Understanding the role of radiologists in complex treatment decisions for patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver and represents a significant global health burden. Management of HCC can be challenging due to multiple factors, including variable expectations for treatment outcomes. Several treatment options are available, each with specific eligibility and ineligibility criteria, and are provided by a multidisciplinary team of specialists. Radiologists should be aware of the types of treatment options available, as well as the criteria guiding the development of individualized treatment plans. This awareness enables radiologists to contribute effectively to patient-centered multidisciplinary tumor boards for HCC and play a central role in reassessing care plans when the treatment response is deemed inadequate. This comprehensive review aims to equip radiologists with an overview of HCC staging systems, treatment options, and eligibility criteria. The review also discusses the significance of imaging in HCC diagnosis, treatment planning, and monitoring treatment response. Furthermore, we highlight the crucial branch points in the treatment decision-making process that depend on radiological interpretation.

Update on Locoregional Therapies for Liver Cancer: Radiation Segmentectomy

Over 900,000 people worldwide were diagnosed with liver cancer in 2022 alone, with hepatocellular carcinoma (HCC) accounting for 75-85% of cases. Treatment for HCC includes some combination of systemic therapies, surgery, liver transplantation, ablation, and intra-arterial therapies with transarterial chemoembolization (TACE) or transarterial radioembolization (TARE). Currently, the Barcelona Clinic Liver Cancer (BCLC) guidelines have acknowledged liver transplantation, surgical resection, and thermal ablation as curative therapies in very early to early stage HCC (BCLC-0 and BCLC-A). While these modalities are the preferred curative treatments for a very early to early stage disease, there are challenges associated with these options, such as organ availability and patient eligibility. Current data shows the role of radiation segmentectomy as a curative therapeutic option for very early to early stage HCC that is unresectable and not amenable to ablation. As future data continues to elucidate the ability for radiation segmentectomy to achieve complete pathologic necrosis, the goal is for the BCLC staging model to acknowledge its role as a curative treatment in this patient population and incorporate it into the ever-evolving guidelines.

Segmental Yttrium-90 Radioembolization Using Glass Microspheres Greater than 400 Gray for the Treatment of Intrahepatic Cholangiocarcinoma: A Preliminary Experience

Radiation segmentectomy with a dose of >190 Gy using yttrium-90 (90Y) glass microspheres for intrahepatic cholangiocarcinoma (iCCA) has been shown to be safe and effective. The present study further increased the dose to >400 Gy for treatment of iCCA as complete pathologic necrosis has been shown in hepatocellular carcinoma using this ablative approach. A total of 10 patients with 13 tumors (median size, 5.3 cm; range, 1.5-13.6 cm) at a single institution underwent >400-Gy segmental radioembolization. Objective response was achieved in all tumors (13 of 13, 100%). One patient developed a Grade 3 or greater major adverse event (stroke and hepatic decompensation). One patient was bridged to transplant (>95% pathologic necrosis), whereas another underwent resection (>99% necrosis). Contralateral hypertrophy was observed in 6 out of 6 patients treated with modified lobectomy dosing, with a functional liver reserve increase from a median of 31.5% to 57.1%. The present report suggests that segmental transarterial radioembolization with >400 Gy is feasible in terms of safety and effectiveness for treating iCCA.

Partition Dosimetry and Outcomes of Metastatic Neuroendocrine Tumors after Yttrium-90 Resin Microsphere Radioembolization

PURPOSE

To characterize estimated mean tumor-absorbed dose (ADT) and objective response of metastatic neuroendocrine tumor (NET) after resin microsphere yttrium-90 (90Y) hepatic radioembolization using partition dosimetry.

MATERIALS AND METHODS

In this retrospective, single-center study, multicompartment dosimetry of index tumors receiving 90Y radioembolization between 2013 and 2022 involved the use of Sureplan (MIM Software, Cleveland, Ohio) and technetium-99m macroaggregated albumin single photon emission computed tomography (SPECT) combined with computed tomography. Thirty-six patients with NET underwent treatment of 56 index tumors. Patients underwent imaging every 3-6 months after treatment to determine best response per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and modified RECIST (mRECIST) criteria. Responses were categorized as objective response (OR) or nonresponse (NR). Wilcoxon rank sum test evaluated differences in continuous variables, and Pearson χ2 test evaluated differences in categorical variables.

RESULTS

Median follow-up was 582 days (IQR, 187-1,227 days). Per RECIST 1.1, 27 patients (75%) experienced OR and 9 patients experienced (25%) NR. Of the 36 patients, 33 (92%) showed hypervascular, mRECIST-evaluable tumors. Among them, 28 patients (85%) showed mRECIST OR and 5 patients (15%) showed NR. The mRECIST OR group received a higher ADT than the NR group (median, 107 Gy; IQR, 95.1-154 Gy vs median, 70.4 Gy; IQR, 62.9-87.6 Gy; P = .048). All tumors receiving at least 120 Gy showed mRECIST OR.

CONCLUSIONS

In hypervascular metastatic NET treated by 90Y resin microsphere radioembolization, higher tumor dose was associated with better tumor response per mRECIST. Doses of ≥120 Gy led to OR.

Demonstrating the Value of Interventional Radiology

While national healthcare expenditures per capita in the United States exceed those in all other Organisation for Economic Co-operation and Development (OECD) countries, measures of health outcomes in the United States lag behind those in peer nations. This combination of high healthcare spending and relatively poor health has led to attempts to identify high- and low-value healthcare services and to develop mechanisms to reimburse health care providers based on the value of the care delivered. This article investigates the meaning of value in healthcare and identifies specific services delivered by interventional radiologists that have accrued evidence that they meet criteria for high-value services. Recognizing the shift in reimbursement to high-value care, it is imperative that interventional radiology (IR) develop the evidence needed to articulate to all relevant stakeholders how IR contributes value to the system.

Contemporary applications of Y90 for the treatment of hepatocellular carcinoma

Transarterial radioembolization (TARE) with yttrium-90 (90Y) microspheres has been widely adopted for the treatment of HCC. Recent advances in yttrium-90 (90Y) dosimetry have led to durable local responses. Radiation segmentectomy has become a viable alternative to thermal ablation for early-stage HCC (Barcelona Clinic Liver Cancer 0 and A) and has been commonly used as a bridge to transplant. TARE is also commonly used for downstaging to transplant using traditional lobar dosimetry and radiation segmentectomy techniques. Radiation lobectomy has a dual role in local tumor control and induction of contralateral liver lobe hypertrophy as a bridge to resection for patients with an inadequate future liver remnant. TARE continues to provide disease control for patients with limited vascular invasion and may be an alternative to systemic therapy for patients with localized advanced disease. The potential synergy between TARE and immunotherapy has been recognized, and prospective studies evaluating this combination are needed for patients with Barcelona Clinic Liver Cancer B and C HCC.

A Phase I/IIa Trial of Yttrium-90 Radioembolization in Combination with Durvalumab for Locally Advanced Unresectable Hepatocellular Carcinoma

PURPOSE

Synergistic effect of radiotherapy and immunotherapy for the treatment of hepatocellular carcinoma (HCC) has been reported. This phase I/IIa pilot trial evaluated preliminary efficacy and safety of combination of radioembolization with yttrium-90 microspheres (Y90-radioembolization) and durvalumab in patients with locally advanced unresectable HCC.

PATIENTS AND METHODS

Patients with Child-Pugh score ≤ 7 and locally advanced HCC, defined as Barcelona Clinic Liver Cancer (BCLC) stage B HCC or BCLC-C disease without extrahepatic metastases, received Y90-radioembolization followed by intravenous durvalumab 1,500 mg 7 to 14 days after Y90-radioembolization and every 4 weeks thereafter. Primary endpoint was time to progression (TTP) assessed by modified RECIST (mRECIST). Secondary endpoints included overall survival (OS), progression-free survival (PFS), objective response rate (ORR) determined by mRECIST, and safety.

RESULTS

All 24 patients enrolled received Y90-radioembolization and 23 received at least one dose of durvalumab. Median follow-up duration was 19.0 months (range, 2.2-24.2). Median TTP was 15.2 months [95% confidence interval (CI), 6.1-not estimated]. Median OS was not reached and 18-month OS rate was 58.3% (95% CI, 36.4-75.0). Median PFS was 6.9 months (95% CI, 5.4-15.2). Seven (29.2%) patients had a complete response and 13 (54.2%) had a partial response; ORR was 83.3% (95% CI, 62.6-95.3). Eleven (47.8%) patients experienced any-grade treatment-related adverse events. Two (8.7%) patients had grade 3 treatment-related adverse events (neutropenia and fever). None experienced any treatment-related serious adverse events.

CONCLUSIONS

In patients with locally advanced unresectable HCC, the combination of Y90-radioembolization and durvalumab demonstrated promising efficacy and safety, warranting further evaluation in large-scale controlled trials.

Friend or Foe? Locoregional Therapies and Immunotherapies in the Current Hepatocellular Treatment Landscape

Over the last several decades, a number of new treatment options for patients with hepatocellular carcinoma (HCC) have been developed. While treatment decisions for some patients remain clear cut, a large numbers of patients have multiple treatment options, and it can be hard for multidisciplinary teams to come to unanimous decisions on which treatment strategy or sequence of treatments is best. This article reviews the available data with regard to two treatment strategies, immunotherapies and locoregional therapies, with a focus on the potential of locoregional therapies to be combined with checkpoint inhibitors to improve outcomes in patients with locally advanced HCC. In this review, the available data on the immunomodulatory effects of locoregional therapies is discussed along with available clinical data on outcomes when the two strategies are combined.

Use of Metformin and Survival in Patients with Hepatocellular Carcinoma (HCC) Undergoing Liver Directed Therapy: Analysis of a Nationwide Cancer Registry

BACKGROUND

Examine the association of metformin use and overall survival (OS) in patients with HCC undergoing image-guided liver-directed therapy (LDT): ablation, transarterial chemoembolization (TACE), or Yttrium-90 radioembolization (Y90 RE).

METHODS

Using National Cancer Institute Surveillance, Epidemiology, and End Results registry and Medicare claims databases between 2007 and 2016, we identified patients ≥ 66 years who underwent LDT within 30 days of HCC diagnosis. Patients with liver transplant, surgical resection, and other malignancies were excluded. Metformin use was identified by at least two prescription claims within 6 months before LDT. OS was measured by time between first LDT and death or last Medicare observation. Comparisons were performed between both all and diabetic patients on and not on metformin.

RESULTS

Of 2746 Medicare beneficiaries with HCC undergoing LDT, 1315 (47.9%) had diabetes or diabetes-related complications. Among all and diabetic patients, 433(15.8%) and 402 (30.6%) were on metformin respectively. Median OS was greater for patients on metformin (19.6 months, 95% CI 17.1-23.0) vs those not (16.0 months, 15.0-16.9; p = 0.0238). Patients on metformin had lower risk of death undergoing ablation (HR 0.70; 0.51-0.95; p = 0.0239) and TACE (HR 0.76, 0.66-0.87; p = 0.0001), but not Y90 RE (HR1.22, 0.89-1.69; p = 0.2231). Among diabetics, OS was greater for those on metformin vs those not (HR 0.77, 0.68-0.88; p < 0.0001). Diabetic patients on metformin had longer OS undergoing TACE (HR 0.71, 0.61-0.83; p < 0.0001), but not ablation (HR 0.74, 0.52-1.04; p = 0.0886) or Y90 RE (HR 1.26, 0.87-1.85; p = 0.2217).

CONCLUSION

Metformin use is associated with improved survival in HCC patients undergoing TACE and ablation.

Using Deep Learning to Predict Treatment Response in Patients with Hepatocellular Carcinoma Treated with Y90 Radiation Segmentectomy

Treatment of hepatocellular carcinoma (HCC) with Y90 radioembolization segmentectomy (Y90-RE) demonstrates a tumor dose-response threshold, where dose estimates are highly dependent on accurate SPECT/CT acquisition, registration, and reconstruction. Any error can result in distorted absorbed dose distributions and inaccurate estimates of treatment success. This study improves upon the voxel-based dosimetry model, one of the most accurate methods available clinically, by using a deep convolutional network ensemble to account for the spatially variable uptake of Y90 within a treated lesion. A retrospective analysis was conducted in patients with HCC who received Y90-RE at a single institution. Seventy-seven patients with 103 lesions met the inclusion criteria: three or fewer tumors, pre- and post treatment MRI, and no prior Y90-RE. Lesions were labeled as complete (n = 57) or incomplete response (n = 46) based on 3-month post treatment MRI and divided by medical record number into a 20% hold-out test set and 80% training set with 5-fold cross-validation. Slice-wise predictions were made from an average ensemble of models and thresholds from the highest accuracy epochs across all five folds. Lesion predictions were made by thresholding all slice predictions through the lesion. When compared to the voxel-based dosimetry model, our model had a higher F1-score (0.72 vs. 0.2), higher accuracy (0.65 vs. 0.60), and higher sensitivity (1.0 vs. 0.11) at predicting complete treatment response. This algorithm has the potential to identify patients with treatment failure who may benefit from earlier follow-up or additional treatment.

Single-Compartment Dose Prescriptions for Ablative 90Y-Radioembolization Segmentectomy

BACKGROUND

Yttrium-90 (⁹⁰Y) radioembolization is increasingly being utilized with curative intent. While single-compartment doses with respect to the perfused volume for the complete pathologic necrosis (CPN) of tumors have been reported, the actual doses delivered to the tumor and at-risk margins that leads to CPN have hitherto not been estimated. We present an ablative dosimetry model that calculates the dose distribution for tumors and at-risk margins based on numerical mm-scale dose modeling and the available clinical CPN evidence and report on the necessary dose metrics needed to achieve CPN following ⁹⁰Y-radioembolization.

METHODS

Three-dimensional (3D) activity distributions (MBq/voxel) simulating spherical tumors were modeled with a 121 × 121 × 121 mm³ soft tissue volume (1 mm³ voxels). Then, 3D dose distributions (Gy/voxel) were estimated by convolving 3D activity distributions with a ⁹⁰Y 3D dose kernel (Gy/MBq) sized 61 × 61 × 61 mm³ (1 mm³ voxels). Based on the published data on single-compartment segmental doses for the resected liver samples of HCC tumors showing CPN after radiation segmentectomy, the nominal voxel-based mean tumor dose (DmeanCPN), point dose at tumor rim (DrimCPN), and point dose 2 mm beyond the tumor boundary (D2mmCPN), which are necessary to achieve CPN, were calculated. The single-compartment dose prescriptions to required achieve CPN were then analytically modeled for more general cases of tumors with diameters dt = 2, 3, 4, 5, 6, and 7 cm and with tumor-to-normal-liver uptake ratios T:N = 1:1, 2:1, 3:1, 4:1, and 5:1.

RESULTS

The nominal case defined to estimate the doses needed for CPN, based on the previously published clinical data, was a single hyperperfused tumor with a diameter of 2.5 cm and T:N = 3:1, treated with a single-compartment segmental dose of 400 Gy. The voxel-level doses necessary to achieve CPN were 1053 Gy for the mean tumor dose, 860 Gy for the point dose at the tumor boundary, and 561 Gy for the point dose at 2 mm beyond the tumor edge. The single-compartment segmental doses necessary to satisfy the criteria for CPN in terms of the mean tumor dose, point dose at the tumor boundary, and the point dose at 2 mm beyond the tumor edge were tabulated for a range of tumor diameters and tumor-to-normal-liver uptake ratios.

CONCLUSIONS

The analytical functions that describe the relevant dose metrics for CPN and, more importantly, the single-compartment dose prescriptions for the perfused volume needed to achieve CPN are reported for a large range of conditions in terms of tumor diameters (1-7 cm) and T:N uptake ratios (2:1-5:1).

Factors Associated With Complete Pathologic Necrosis of Hepatocellular Carcinoma on Explant Evaluation After Locoregional Therapy: A National Analysis Using the UNOS Database

BACKGROUND. Complete pathologic necrosis (CPN) is associated with improved survival in patients who undergo liver transplant (LT) after locoregional therapy (LRT) for hepatocellular carcinoma (HCC). OBJECTIVE. The purpose of this article was to identify patient, HCC, and transplant center characteristics associated with rates of CPN on explant evaluation using a large national sample of patients undergoing LT after LRT for HCC measuring 3 cm or smaller. METHODS. This retrospective study used data from the United Network for Organ Sharing database. The study included 6265 adults (median age, 62 years; 1505 women, 4760 men) who underwent LT after a single type of LRT (either transarterial chemoembolization [TACE], thermal ablation, or transarterial radioembolization [TARE]) for HCCs measuring 3 cm or smaller at one of 118 U.S. transplant centers from April 12, 2012, to March 31, 2020. Patients were classified as having CPN if explant evaluation showed 100% necrosis of all HCCs. Associations with CPN were explored. Centers were categorized into tertiles on the basis of center-level CPN rates, and tertiles were compared. RESULTS. LRT was performed by TACE in 69.5% (4352/6265), thermal ablation in 19.4% (1217/6265), and TARE in 11.1% (696/6265) of patients. CPN rate was 18.5% (805/4352) after TACE, 35.8% (436/1217) after thermal ablation, 33.6% (234/696) after TARE, and 23.5% (1475/6265) overall. In multivariable analysis incorporating age, sex, model for end-stage liver disease score, α-fetoprotein level before LRT, wait list time, number of HCCs, HCC size, and the transplant center (as a random factor), use of thermal ablation (OR, 2.19; 95% CI, 1.86-2.57; p < .001) or TARE (OR, 1.92; 95% CI, 1.57-2.36; p < .001), with TACE as reference, independently predicted greater likelihood of CPN. Center-level CPN rates ranged from 0.0% to 50.0%. With centers stratified by CPN rates, ablation was performed more frequently than TACE in 5.0% of centers in the first, 15.4% in the second, and 23.1% in the third tertiles (p = .07). CONCLUSION. CPN rate on explant evaluation was low. Thermal ablation or TARE, rather than TACE, was associated with higher likelihood of CPN in patient-level and center-level analyses. CLINICAL IMPACT. Findings from this large national sample support a potential role of thermal ablation or TARE for achieving CPN of HCC measuring 3 cm or smaller.

Voxel-S-Value based 3D treatment planning methods for Y-90 microspheres radioembolization based on Tc-99m-macroaggregated albumin SPECT/CT

Partition model (PM) for Y-90 microsphere radioembolization is limited in providing 3D dosimetrics. Voxel-S-Values (VSV) method has good agreement with Monte Carlo (MC) simulations for 3D absorbed dose conversion. We propose a new VSV method and compare its performance along with PM, MC and other VSV methods for Y-90 RE treatment planning based on Tc-99m MAA SPECT/CT. Twenty Tc-99m-MAA SPECT/CT patient data are retrospectively analyzed. Seven VSV methods are implemented: (1) local energy deposition; (2) liver kernel; (3) liver kernel and lung kernel; (4) liver kernel with density correction (LiKD); (5) liver kernel with center voxel scaling (LiCK); (6) liver kernel and lung kernel with density correction (LiLuKD); (7) proposed liver kernel with center voxel scaling and lung kernel with density correction (LiCKLuKD). Mean absorbed dose and maximum injected activity (MIA) obtained by PM and VSV are evaluated against MC results, and 3D dosimetrics generated by VSV are compared with MC. LiKD, LiCK, LiLuKD and LiCKLuKD have the smallest deviation in normal liver and tumors. LiLuKD and LiCKLuKD have the best performance in lungs. MIAs are similar by all methods. LiCKLuKD could provide MIA consistent with PM, and precise 3D dosimetrics for Y-90 RE treatment planning.

Yttrium-90 Radiation Segmentectomy in Oligometastatic Secondary Hepatic Malignancies

PURPOSE

To evaluate the safety and efficacy of yttrium-90 (⁹⁰Y) radiation segmentectomy (RS) in the treatment of oligometastatic secondary hepatic malignancies.

MATERIALS AND METHODS

This institutional review board-approved retrospective study evaluated 16 patients with oligometastatic secondary hepatic malignancies who were treated with RS. The median patient age was 61.9 years (range, 38.6-85.7 years). Of the 16 patients, 11 (68.8%) presented with solitary lesions. The median index tumor size was 3.1 cm (95% CI, 2.3-3.9). Primary outcomes were evaluation of clinical and biochemical toxicities using National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0, and imaging response using Response Evaluation Criteria in Solid Tumors, version 1.1. Secondary outcomes were time to progression (TTP) and overall survival (OS) as estimated by the Kaplan-Meier method.

RESULTS

Clinical Grade 3 toxicities were limited to 1 (6.7%) patient who experienced fatigue, abdominal pain, nausea, and vomiting. Biochemical Grade 3 toxicities occurred in 1 (6.7%) patient who experienced lymphopenia. No Grade 4 clinical or biochemical toxicities were identified. Disease control was achieved in 14 (93.3%) of 15 patients. The median TTP of the treated tumor was 72.9 months (95% CI, 11.2 to no estimate). The median OS was 60.9 months (95% CI, 24.7 to no estimate).

CONCLUSIONS

⁹⁰Y RS displayed an excellent safety profile and was effective in achieving a high disease control rate in the treatment of oligometastatic secondary hepatic malignancies.

Maximum tumor-absorbed dose measured by voxel-based multicompartmental dosimetry as a response predictor in yttrium-90 radiation segmentectomy for hepatocellular carcinoma

OBJECTIVE

Advances in hepatic radioembolization are based on a selective approach with radical intent and the use of multicompartment dosimetric analysis. The objective of this study is to assess the utility of voxel-based dosimetry in the quantification of actual absorbed doses in radiation segmentectomy procedures and to establish cutoff values predictive of response.

METHODS

Ambispective study in hepatocarcinoma patients treated with radiation segmentectomy. Calculated dosimetric parameters were mean tumor-absorbed dose, maximum tumor AD, minimal tumor AD in 30, 50, and 70% of tumor volume and mean AD in non-tumor liver. The actual absorbed dose (aAD) was calculated on the Y-90-PET/CT image using 3D voxel-based dosimetry software. To assess radiological response, localized mRECIST criteria were used. The objective response rate (ORR) was defined as CR or PR.

RESULTS

Twenty-four HCC patients, BCLC 0 (5), A (17) and B (2) were included. The mean yttrium-90 administered activity was 1.38 GBq in a mean angiosome volume of 206.9 cc and tumor volume 56.01 cc. The mean theoretical AD was 306.3 Gy and aAD 352 Gy. A very low concordance was observed between both parameters (rho_c 0.027). ORR at 3 and 6 m was 84.21% and 92.31%, respectively. Statistically significant relationship was observed between the maximum tumor-absorbed dose and complete radiological response at 3 m (p 0.022).

CONCLUSION

A segmental approach with radical intention leads to response rates greater than 90%, being the tumor maximum absorbed dose the dosimetric parameter that best predicts radiological response in voxel-based dosimetry.