Side effects of yttrium-90 radioembolization

Adverse reactions to therapeutic radiopharmaceuticals

Radiopharmaceuticals are drugs used in treatment or diagnosis that contain a radioactive part, usually a pharmaceutical part in their structure. Adverse drug reactions are harmful and unexpected responses that occur when administered at normal doses. Although radiopharmaceuticals are regarded as safe medical products, adverse reactions should not be ignored. More serious adverse reactions such as myelosuppression, pleural effusion, and death may develop in therapeutic radiopharmaceuticals due to their use at higher doses than those used in diagnosis. Therefore, monitoring adverse reactions and reporting them to health authorities is important. This review aims to provide information about adverse reactions that may be related to radiopharmaceuticals used in treatment.

New frontiers in radioembolization

Radioembolization is a locoregional transarterial therapy that combines radionuclide and micron-sized beads to deliver radiation internally to the target tumors based on the arterial blood flow. While initially developed as a palliative treatment option, radioembolization is now used for curative intent treatment, neoadjuvant therapy, and method to downstage or bridge for liver transplant. Radioembolization has become increasingly utilized and is an important therapeutic option for the management of hepatocellular carcinoma and liver metastasis. This article provides an overview of the techniques, challenges, and novel developments in radioembolization, including new dosimetry techniques, radionuclides, and new target tumors.

Yttrium-90 Induces an Effector Memory Response with Neoantigen Clonotype Expansion: Implications for Immunotherapy

Yttrium-90 (90Y) transarterial radioembolization can safely and effectively treat hepatocellular carcinoma (HCC). Clinical trials combining 90Y with immunotherapy are aimed at improving treatment response rates. The impact of transient 90Y-induced lymphopenia on T-cell homeostasis and functional dynamics is unknown. Paired blood specimens were collected prior to first-cycle 90Y and at imaging follow-up in patients with HCC Barcelona Clinic Liver Cancer stages A-B. Flow cytometry and T-cell receptor (TCR) sequencing were used to monitor changes in T-cell subsets and TCR repertoire following 90Y. Objective response (OR) rates were determined using modified RECIST and defined as either OR or nonobjective response. Time-to-progression (TTP) was defined as progression to Barcelona Clinic Liver Cancer stage C within 6 months following 90Y. 90Y induced shifts in both CD4+ (P = 0.049) and CD8+ (P < 0.001) toward an effector memory T-cell response independent of treatment response rate. Nonresponders to 90Y were characterized by a sustained elevation in both naïve CD4+ cells (P = 0.019) and programmed cell death protein 1 expression in CD8+ cells (P = 0.003). Paired analysis of the TCR repertoire revealed a variable induction of neoantigen clonotypes and expansion of existing clonotypes independent of 90Y response. In patients with an OR, changes in TCR clonality did not influence TTP. However, polyclonal profiles in patients without an OR were associated with shorter TTP (P = 0.005; HR, 10.8) and 75% disease progression rates 6 months following treatment. 90Y induces a population shift from central to effector memory accompanied by neoantigen T-cell responses independent of treatment response rate. Monoclonal shifts in the post-90Y T-cell repertoire had superior overall TTP and improved TTP in patients with a first-cycle nonobjective response.

SIGNIFICANCE

90Y can safely treat HCC; however, it causes transient lymphopenia. In this article, 90Y stimulates a peripheral effector memory response independent of initial treatment response. TCR sequencing revealed that polyclonal profiles in patients without an OR to treatment were associated with rapid progression rates 6 months after 90Y.

Diagnosis and management of radiation cholecystitis as a complication of Y90 radioembolization for hepatocellular carcinoma

Radiation induced cholecystitis is a known but rare complication of Yttrium90 (Y90) radioembolization of hepatic tumors due to nontarget embolization. Many documented cases of radiation induced cholecystitis have been treated with cholecystectomy, which is significant given the typical patient population undergoing radioembolization tends to be of higher surgical risk. Here, we present a case of a 68 year old male who developed radiation induced cholecystitis status post hepatic radioembolization that resolved with conservative management alone. This case highlights that radiation induced cholecystitis may be successfully and safely treated conservatively.

Intensive locoregional therapy before liver transplantation for colorectal cancer liver metastasis: A novel pretransplant protocol

We describe a novel pre-liver transplant (LT) approach in colorectal liver metastasis, allowing for improved monitoring of tumor biology and reduction of disease burden before committing a patient to transplantation. Patients undergoing LT for colorectal liver metastasis at Cleveland Clinic were included. The described protocol involves intensive locoregional therapy with systemic chemotherapy, aiming to reach minimal disease burden revealed by positron emission tomography scan and carcinoembryonic Ag. Patients with no detectable disease or irreversible treatment-induced liver injury undergo transplant. Nine patients received liver transplant out of 27 who were evaluated (33.3%). The median follow-up was 700 days. Seven patients (77.8%) received a living donor LT. Five had no detectable disease, and 4 had treatment-induced cirrhosis. Pretransplant management included chemotherapy (n = 9) +/- bevacizumab (n = 6) and/or anti-EGFR (n = 6). The median number of pre-LT cycles of chemotherapy was 16 (range 10-40). Liver-directed therapy included Yttrium-90 (n = 5), ablation (n = 4), resection (n = 4), and hepatic artery infusion pump (n = 3). Three patients recurred after LT. Actuarial 1- and 2-year recurrence-free survival were 75% (n = 6/8) and 60% (n = 3/5). Recurrence occurred in the lungs (n = 1), liver graft (n = 1), and lungs+para-aortic nodes (n = 1). Patients with pre-LT detectable disease had reduced RFS ( p = 0.04). All patients with recurrence had histologically viable tumors in the liver explant. Patients treated in our protocol (n = 16) demonstrated improved survival versus those who were not candidates (n = 11) regardless of transplant status ( p = 0.01). A protocol defined by aggressive pretransplant liver-directed treatment and transplant for patients with the undetectable disease or treatment-induced liver injury may help prevent tumor recurrence.

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.

MIDOS: a novel stochastic model towards a treatment planning system for microsphere dosimetry in liver tumors

PURPOSE

Transarterial radioembolization (TARE) procedures treat liver tumors by injecting radioactive microspheres into the hepatic artery. Currently, there is a critical need to optimize TARE towards a personalized dosimetry approach. To this aim, we present a novel microsphere dosimetry (MIDOS) stochastic model to estimate the activity delivered to the tumor(s), normal liver, and lung.

METHODS

MIDOS incorporates adult male/female liver computational phantoms with the hepatic arterial, hepatic portal venous, and hepatic venous vascular trees. Tumors can be placed in both models at user discretion. The perfusion of microspheres follows cluster patterns, and a Markov chain approach was applied to microsphere navigation, with the terminal location of microspheres determined to be in either normal hepatic parenchyma, hepatic tumor, or lung. A tumor uptake model was implemented to determine if microspheres get lodged in the tumor, and a probability was included in determining the shunt of microspheres to the lung. A sensitivity analysis of the model parameters was performed, and radiation segmentectomy/lobectomy procedures were simulated over a wide range of activity perfused. Then, the impact of using different microspheres, i.e., SIR-Sphere®, TheraSphere®, and QuiremSphere®, on the tumor-to-normal ratio (TNR), lung shunt fraction (LSF), and mean absorbed dose was analyzed.

RESULTS

Highly vascularized tumors translated into increased TNR. Treatment results (TNR and LSF) were significantly more variable for microspheres with high particle load. In our scenarios with 1.5 GBq perfusion, TNR was maximum for TheraSphere® at calibration time in segmentectomy/lobar technique, for SIR-Sphere® at 1-3 days post-calibration, and regarding QuiremSphere® at 3 days post-calibration.

CONCLUSION

This novel approach is a decisive step towards developing a personalized dosimetry framework for TARE. MIDOS assists in making clinical decisions in TARE treatment planning by assessing various delivery parameters and simulating different tumor uptakes. MIDOS offers evaluation of treatment outcomes, such as TNR and LSF, and quantitative scenario-specific decisions.

Analyzing risk factors and developing a stratification system for hepatocellular carcinoma recurrence after interferon-free direct-acting antiviral therapy in chronic hepatitis C patients

BACKGROUND

The introduction of direct-acting antiviral agents (DAAs) has revolutionized the therapeutic landscape of chronic hepatitis C (CHC), however real-world data on the risk factors of hepatocellular carcinoma (HCC) recurrence following DAA treatment in CHC-HCC patients are limited in Taiwan. We aimed to evaluate the therapeutic efficacy of DAAs in Taiwanese patients with prior hepatitis C virus (HCV)-induced HCC and identify the posttreatment risk factors for HCC recurrence.

METHODS

Between January 2017 and August 2021, 208 CHC-HCC patients underwent DAA treatment at Taipei Veterans General Hospital. Among them, 94 patients met the inclusion criteria (Barcelona clinic liver cancer [BCLC] stage 0/A after treatment with complete radiological response) for analysis. Comprehensive demographic, clinical, and laboratory data were collected before and after DAA treatment. The primary outcome was HCC recurrence post-DAA treatment, and independent variables were assessed using multivariate Cox proportional hazards models.

RESULTS

The mean age of the enrolled patients was 75.9 ± 8.9 years; 44.7% were male, and 94.7% were Child-Pugh class A. Before DAA treatment, 31.9% experienced HCC recurrence. The median follow-up after DAA treatment was 22.1 months (interquartile range, 8.6-35.9 months). After treatment, 95.7% of the patients achieved a sustained virological response (SVR 12 ), but HCC recurrence occurred in 54.3%. Cumulative HCC recurrence rates after treatment were 31.1% at 1 year, 57.3% at 3 years, and 68.5% at up to 5.69 years. Multivariate analysis revealed that prior HCC recurrence before DAA treatment (hazard ratio [HR] = 3.15, p = 0.001), no SVR 12 after treatment (HR = 6.829, p = 0.016), 12-week posttreatment alpha-fetoprotein (AFP) level >10 ng/mL (HR = 2.34, p = 0.036), and BCLC A3 lesions (two or three nodules without any tumor exceeding 3 cm) (HR = 2.31, p = 0.039) were independent risk factors for HCC recurrence. We further developed a risk stratification system based on these significant independent factors.

CONCLUSION

This investigation underscores the critical influence of factors such as prior HCC recurrence, successful attainment of SVR 12 , posttreatment AFP level, and specific tumor characteristics in determining the risk of HCC recurrence after treatment with DAAs. Our proposed innovative risk stratification system may not only contribute to enhanced personalized care but also holds the potential to optimize treatment outcomes.

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.

Quantitative differences in volumetric calculations for radiation dosimetry in segmental Y90 treatment planning using hybrid angiography-CT compared with anatomic segmentation

OBJECTIVE

To compare treatment volumes reconstructed from hybrid Angio-CT catheter-directed infusion imaging and Couinaud anatomic model as well as the implied differences in Y-90 radiation dosimetry.

METHODS

Patients who underwent transarterial radioembolization (TARE) using Y-90 glass microspheres with pretreatment CT or MRI imaging as well as intraprocedural angiography-CT (Angio-CT) were analysed. Treatment volumes were delineated using both tumoural angiosomes (derived from Angio-CT) and Couinaud anatomic landmarks. Segmental and lobar treatment volumes were calculated via semi-automated contouring software. Volume and dose differences were compared by the two-tailed Student t test or Wilcoxon signed-rank test. Factors affecting volume and dose differences were assessed via simple and/or multiple variable linear regression analysis.

RESULTS

From September 2018 to March 2021, 44 patients underwent 45 lobar treatments and 38 patients received 56 segmental treatments. All target liver lobes and all tumours were completely included within the field-of-view by Angio-CT. Tumour sizes ranged between 1.1 and 19.5 cm in diameter. Segmental volumes and treatment doses were significantly different between the Couinaud and Angio-CT volumetry methods (316 vs 404 mL, P < .0001 and 253 vs 212 Gy, P < .01, respectively). Watershed tumours were significantly correlated with underestimated volumes by the Couinaud anatomic model (P < .001). There was a significant linear relationship between tumour diameter and percent volume difference (R2 = 0.44, P < .0001). The Couinaud model overestimated volumes for large tumours that exhibited central hypovascularity/necrosis and for superselected peripheral tumours.

CONCLUSIONS

Angio-CT may confer advantages over the Couinaud anatomic model and enable more accurate, personalized dosimetry for TARE.

ADVANCES IN KNOWLEDGE

Angio-CT may confer advantages over traditional cross-sectional and cone-beam CT imaging for selective internal radiation therapy planning.

Practical Considerations When Choosing Chemoembolization versus Radioembolization for Hepatocellular Carcinoma

Transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) are common liver-directed therapies (LDTs) for unresectable HCC. While both deliver intra-arterial treatment directly to the site of the tumor, they differ in mechanisms of action and side effects. Several studies have compared their side effect profile, time to progression, and overall survival data, but often these lack practical considerations when choosing which treatment modality to use. Many factors can impact operator's choice for treatment, and the choice depends on treatment availability, cost, insurance coverage, operator's comfort level, patient-specific factors, tumor location, tumor biology, and disease stage. This review discusses survival data, time to progression data, as well as more practical patient and tumor characteristics for personalized LDT with TACE or TARE.

Downstaging Techniques for Hepatocellular Carcinoma in Candidates Awaiting Liver Transplantation

During the last decade, downstaging for hepatocellular carcinoma has expanded the pool of patients eligible for liver transplantation. The literature is rife with attempts to elucidate best treatment strategies with novel locoregional and systemic therapies continuing to emerge. Several trials have confirmed the large-scale success of downstaging protocols, with equitable long-term survival and recurrence rates after liver transplant. We review the currently available techniques used for downstaging, including their indications, complications, and efficacies. New frontiers have focused on the potential role of immunotherapy in the neoadjuvant setting, although more research is needed to delineate its role in current treatment paradigms.

Lineage-specific regulation of PD-1 expression in early-stage hepatocellular carcinoma following 90yttrium transarterial radioembolization - Implications in treatment outcomes

BACKGROUND

Hepatocellular carcinoma (HCC) remains one of the leading causes of cancer-related deaths in the world. Liver-directed therapies, including 90Yttrium (90Y) radioembolization, play an integral role in the management of HCC with excellent response rates. This has led to clinical trials of immunotherapy in combination with 90Y. Elevated PD-1 expression and lymphopenia were recently shown as risk factors for disease progression in early-stage HCC treated with liver-directed therapies. The aim of this study was to investigate PD-1 expression dynamics in bridge/downstage to transplant in HCC patients receiving first-cycle 90Y and evaluate the impact of these changes on response rates and time-to-progression (TTP).

METHODS

Patients with HCC receiving first-cycle 90Y as a bridge to liver transplantation (n = 99) were prospectively enrolled. Blood specimens were collected before 90Y and again during routine imagining follow-up to analyze PD-1 expression via flow cytometry. Complete and objective response rates (CR and ORR) were determined using mRECIST.

RESULTS

In 84/88 patients with available follow-up imaging, 83% had a localized ORR with 63% having localized CR. For overall response, 71% and 54% experienced ORR and CR, respectively. Post-90Y PD-1 upregulation in CD8 + associated with HCC progression and decreased TTP. Treatment with 90Y was associated with an anticipated significant post-treatment drop in lymphocytes (P < 0.001) that was independent of PD-1 expression for either CD4+ or CD8+ T cells (P = 0.751 and P = 0.375) and not associated with TTP risk. The change in lymphocytes was not correlated with PD-1 expression following treatment nor TTP.

CONCLUSIONS

Elevated PD-1 expression on peripheral T cells is associated with increased risk of HCC progression and shorter time to progression in bridging/downstaging to transplant HCC patients undergoing first-cycle 90Y. Treatment-induced lymphopenia was not associated with treatment response, or increased progression risk, suggesting this anticipated adverse event does not impact short-term HCC outcomes.

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.

Current status of yttrium-90 microspheres radioembolization in primary and metastatic liver cancer

Liver malignancy, including primary liver cancer and metastatic liver cancer, has become one of the most common causes of cancer-related death worldwide due to the high malignant degree and limited systematic treatment strategy. Radioembolization with yttrium-90 (90Y)-loaded microspheres is a relatively novel technology that has made significant progress in the local treatment of liver malignancy. The different steps in the extensive work-up of radioembolization for patients with an indication for treatment with 90Y microspheres, from patient selection to follow up, both technically and clinically, are discussed in this paper. It describes the application and development of 90Y microspheres in the treatment of liver cancer.

Pre-treatment dosimetry in90Y-SIRT: Is it possible to optimise SPECT reconstruction parameters and calculation methods for accurate dosimetry?

PURPOSE

The aim of this study was (a) to optimise the99mTc-SPECT reconstruction parameters for the pre-treatment dosimetry of90Y-selective internal radiation therapy (SIRT) and (b) to compare the accuracy of clinical dosimetry methods with full Monte-Carlo dosimetry (fMCD) performed with Gate.

METHODS

To optimise the reconstruction parameters, two hundred reconstructions with different parameters were performed on a NEMA phantom, varying the number of iterations, subsets, and post-filtering. The accuracy of the dosimetric methods was then investigated using an anthropomorphic phantom. Absorbed dose maps were generated using (1) the Partition Model (PM), (2) the Dose Voxel Kernel (DVK) convolution, and (3) the Local Deposition Method (LDM) with known activity restricted to the whole phantom (WP) or to the liver and lungs (LL). The dose to the lungs was calculated using the "multiple DVK" and "multiple LDM" methods.

RESULTS

Optimal OSEM reconstruction parameters were found to depend on object size and dosimetric criterion chosen (Dmean or DVH-derived metric). The Dmean of all three dosimetric methods was close (≤ 10%) to the Dmean of fMCD simulations when considering large segmented volumes (whole liver, normal liver). In contrast, the Dmean to the small volume (∅=31) was systemically underestimated (12%-25%). For lungs, the "multiple DVK" and "multiple LDM" methods yielded a Dmean within 20% for the WP method and within 10% for the LL method.

CONCLUSIONS

All three methods showed a substantial degradation of the dose-volume histograms (DVHs) compared to fMCD simulations. The DVK and LDM methods performed almost equally well, with the "multiple DVK" method being more accurate in the lungs.

Recent Advances in Locoregional Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is responsible for 90% of primary hepatic cancer cases, and its incidence with associated morbidity and mortality is growing worldwide. In recent decades, there has been a revolution in HCC treatment. There are three main types of locoregional therapy: radiofrequency ablation, transarterial chemoembolisation, and transarterial radioembolisation. This article summarises recent advances in locoregional methods.

Evaluation of results after 112 radioembolizations with 90Y-microspheres

AIM

To determine the results of radioembolization transarterial (TARE), in the treatment of liver tumors, a retrospective evaluation was performed after 112 TARE with ⁹⁰Y-microspheres administered in 82 patients in a single hospital, analyzing efficacy and safety, after a follow-up greater than or equal to 1 year post-TARE in all patients, and evaluating the possible relationship between treatment response and patient survival.

MATERIAL AND METHODS

We have administered 57 single TARE and 55 multiple TARE in patients with hepatocellular carcinoma (53), liver metastases (25) and cholangiocarcinoma (4), with prior multidisciplinary evaluation, clinical, angiographic and gammagraphic (planar/SPECT/SPECT-CT with ^99mTc-MAA), multicompartment model (MIRD equations), post-TARE screening (planar/SPECT/SPECT-CT), clinical and radiological follow-up, tumor response evaluation (mRECIST criteria) and Kaplan-Meier analysis to determine progression-free survival and overall survival (OS).

RESULTS

Therapeutic intention was palliative (82%) and as bridge to liver transplantation/surgical resection (17%). We obtained response (R), complete or partial, in 65.9% of cases. One year after TARE 34.7% of patients with R and 19.2% of non-R were progression-free (p: 0.003), with OS of 80% for R and 37.5% for non-R (p: 0.001). Survival analysis showed median OS of 18 months (95% CI 15.7-20.3) for R and 9 months (95% CI 6.1-11.8) for non-R (p: 0.03). We found mild (27.6%) and severe (5.3%) side effects, all of them resolved, without higher incidence after multiple TARE.

CONCLUSION

TARE with ⁹⁰Y-microspheres, in appropriately selected patients with liver tumors, provides therapeutic efficacy and low rate of toxicity, with higher progression-free survival and OS in patients with TARE response compared to those who did not respond.

Selective internal radiotherapy in Germany: a review of indications and hospital mortality from 2012 to 2019

Background and Aim

Selective internal radiotherapy (SIRT) is a minimal invasive tumor therapy for hepatocellular carcinoma (HCC), biliary tract cancer (BTC), and liver metastasis of extrahepatic tumors. Comprehensive data on past and current trends of SIRT as well as outcome parameters such as in-hospital mortality and adverse events in Germany are missing.

Methods

We evaluated current clinical developments and outcomes of SIRT in Germany based on standardized hospital discharge data, provided by the German Federal Statistical Office from 2012 to 2019.

Results

A total of 11,014 SIRT procedures were included in the analysis. The most common indication was hepatic metastases (54.3%; HCC: 39.7%; BTC: 6%) with a trend in favor of HCC and BTC over time. Most SIRTs were performed with yttrium-90 (99.6%) but the proportion of holmium-166 SIRTs increased in recent years. There were significant differences in the mean length of hospital stay between ⁹⁰Y (3.67 ± 2 days) and ¹⁶⁶Ho (2.9 ± 1.3 days) based SIRTs. Overall in-hospital mortality was 0.14%. The mean number of SIRTs/hospital was 22.9 (SD ± 30.4). The 20 highest case volume centers performed 25.6% of all SIRTs.

Conclusion

Our study gives a detailed insight into indications, patient-related factors, and the incidence of adverse events as well as the overall in-hospital mortality in a large SIRT collective in Germany. SIRT is a safe procedure with low overall in-hospital mortality and a well-definable spectrum of adverse events. We report differences in the regional distribution of performed SIRTs and changes in the indications and used radioisotopes over the years.

Relevance for Patients

SIRT is a safe procedure with very low overall mortality and a well-definable spectrum of adverse events, particularly gastrointestinal. Complications are usually treatable or self-limiting. Acute liver failure is a potentially fatal but exceptionally rare complication. ¹⁶⁶Ho has promising beneficial bio-physical characteristics and ¹⁶⁶Ho-based SIRT should be further evaluated against ⁹⁰Y-based SIRT as the current standard of care.

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.

Microspheres as a Carrier System for Therapeutic Embolization Procedures: Achievements and Advances

The targeted delivery of anti-cancer drugs and isotopes is one of the most pursued goals in anti-cancer therapy. One of the prime examples of such an application is the intra-arterial injection of microspheres containing cytostatic drugs or radioisotopes during hepatic embolization procedures. Therapy based on the application of microspheres revolves around vascular occlusion, complemented with local therapy in the form of trans-arterial chemoembolization (TACE) or radioembolization (TARE). The broadest implementation of these embolization strategies currently lies within the treatment of untreatable hepatocellular cancer (HCC) and metastatic colorectal cancer. This review aims to describe the state-of-the-art TACE and TARE technologies investigated in the clinical setting for HCC and addresses current trials and new developments. In addition, chemical properties and advancements in microsphere carrier systems are evaluated, and possible improvements in embolization therapy based on the modification of and functionalization with therapeutical loads are explored.

Yttrium-90 Radioembolization: Current Indications and Outcomes

BACKGROUND

Radioembolization (RE) with 90Yttrium (Y90) has generally been used to treat patients with advanced disease. Recent data suggest, however, that RE is also safe and feasible to treat patients with early or intermediate stage disease. We herein review the current evidence regarding the use of RE with Y90 for patients with HCC.

METHODS

A comprehensive review of the literature was performed using MEDLINE/PubMed and Web of Science databases with a search end date of August 1, 2022.

RESULTS

Patients with HCC are often treated according to the BCLC staging system. Among patients with early-stage HCC (BCLC A), intermediate-stage HCC (BCLC B), and advanced-stage HCC (BCLC C), RE with Y90 has demonstrated promising results with comparable overall survival, time to disease progression, and radiological response compared with other standard of care treatment modalities. Moreover, Y90 RE can be used as a downstaging treatment modality for patients with advanced HCC who have a disease burden that is initially outside LT criteria. Radiation lobectomy (RL) has been described as a treatment modality with the intent of treating the ipsilateral liver that harbors the HCC, while also causing compensatory hypertrophy of the future liver remnant (FLR).

CONCLUSION

While initially considered as a palliative option for HCC patients, Y90 RE has emerged as an important part of the multi-modality care of patients with HCC across a wide spectrum of clinical indications.

Interventions for unresectable intrahepatic cholangiocarcinoma: a network meta‐analysis

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To establish the existence of differences in effectiveness and safety of intra‐arterial therapies (IATs) such as bland embolisation, conventional transarterial chemoembolisation (cTACE), drug‐eluting bead transarterial chemoembolisation (DEBTACE), yttrium‐90 (Y90), hepatic artery infusion (HAI), external beam radiotherapies (EBRTs), and immunotherapy versus systemic chemotherapy for unresectable intrahepatic cholangiocarcinoma through pairwise meta‐analysis and network meta‐analysis with subsequent treatment ranking.

Selective internal radiation therapy of metastatic breast cancer to the liver: A meta-analysis

Introduction

The aim of this study is to conduct a meta-analysis to assess the efficacy of yttrium-90 selective internal radiation therapy (SIRT) in treating patients with breast cancer with hepatic metastasis.

Method

PubMed and The Cochrane Library were queried from establishment to January 2021. The following keywords were implemented: "breast", "yttrium", and "radioembolization". The following variables and outcomes were collected: publication year, region, sample size, study design, presence of extrahepatic disease, tumor burden, infused radioactivity, breast cancer subtype, previous treatment, median survival time (MST), length of follow-up, adverse events, and radiographical response such as Response Evaluation Criteria in Solid Tumors (RECIST), modified RECIST (mRECIST), and Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST).

Results

A total of 24 studies from 14 institutions were included in the present meta-analysis. On the basis of the data from 412 patients, post-embolization MST was 9.8 [95% confidence interval (CI): 9.0-11.6] months. Patients with additional extrahepatic metastasis had a poorer survival rate compared with those with localized hepatic metastasis only (MST: 5.3 vs. 15 months, p < 0.0001). Patients with <25% liver tumor burden exhibited more promising survival than those with >25% (MST: 10.5 vs. 6.8 months, p < 0.0139). On the basis of RECIST, mRECIST, and PERCIST criteria, tumor response rate was 36% (95% CI: 26%-47%), 49% (95% CI: 34%-65%), and 47% (95% CI: 17%-78%), respectively, whereas tumor control rate was 85% (95% CI: 76%-93%), 73% (95% CI: 59%-85%), and 97% (95% CI: 91%-100%), respectively.

Conclusion

On the basis of the available published evidence, SIRT is feasible and effective in treating patients with breast cancer with liver metastasis. Patients with lower hepatic tumor burden and without extrahepatic metastasis demonstrated more survival benefit. Future randomized controlled trials are warranted.

Radiochemical Feasibility of Mixing of 99mTc-MAA and 90Y-Microspheres with Omnipaque Contrast

Yttrium-90 (90Y) microspheres are widely used for the treatment of liver-dominant malignant tumors. They are infused via catheter into the hepatic artery branches supplying the tumor under fluoroscopic guidance based on pre-therapy angiography and Technetium-99m macroaggregated albumin (99mTc-MAA) planning. However, at present, these microspheres are suspended in radiolucent media such as dextrose 5% (D5) solution. In order to monitor the real-time implantation of the microspheres into the tumor, the 90Y microspheres could be suspended in omnipaque contrast for allowing visualization of the correct distribution of the microspheres into the tumor. The radiochemical purity of mixing 90Y-microspheres in various concentrations of omnipaque was investigated. The radiochemical purity and feasibility of mixing 99mTc-MAA with various concentrations of a standard contrast agent were also investigated. Results showed the radiochemical feasibility of mixing 90Y-microspheres with omnipaque is radiochemically acceptable for allowing real-time visualization of radioembolization under fluoroscopy.

Lipid-polymer nanocarrier platform enables X-ray induced photodynamic therapy against human colorectal cancer cells

In this study, we brought together X-ray induced photodynamic therapy (X-PDT) and chemo-drug (5-FU) for the treatment on colorectal cancer cells. This was achieved by developing a lipid-polymer hybrid nanoparticle delivery system (FA-LPNPs-VP-5-FU). It was prepared by incorporating a photosensitizer (verteporfin), chemotherapy drug (5-FU) and a targeting moiety (folic acid) into one platform. The average size of these nanoparticles was around 100 nm with low polydispersity. When exposed to clinical doses of 4 Gy X-ray radiation, FA-LPNPs-VP-5-FU generated sufficient amounts of reactive oxygen species, triggering the apoptosis and necrosis pathway of cancer cells. Our combined X-PDT and chemo-drug strategy was effective in inhibiting cancer cells' growth and proliferation. Cell cycle analyses revealed that our treatment induced G2/M and S phase arrest in HCT116 cells. Our results indicate that this combined treatment provides better antitumour effect in colorectal cancer cells than each of these modalities alone. This may offer a novel approach for effective colorectal cancer treatment with reduced off-target effect and drug toxicity.

Oncologic Interventions: Periprocedural Medications

Significant advances in ablative and endovascular therapies have allowed interventional radiology to play a substantial role in the management of patients with malignant neoplasms. The evolution of these procedures and the optimization of patient outcomes and experience must take into account various elements of the periprocedural period. Some of the most important considerations within the periprocedural period are the pharmacologic agents used to avoid infectious complications, decrease pain, and manage side effects. In this article, we discuss some of the most commonly used medications in interventional oncology procedures including antibiotics, narcotics, sedatives, antiemetics, and others.

Intraarterial Therapies for the Management of Hepatocellular Carcinoma

Image-guided locoregional therapies play a crucial role in the management of patients with hepatocellular carcinoma (HCC). Transarterial therapies consist of a group of catheter-based treatments where embolic agents are delivered directly into the tumor via their supplying arteries. Some of the transarterial therapies available include bland embolization (TAE), transarterial chemoembolization (TACE), drug-eluting beads-transarterial chemoembolization (DEB-TACE), selective internal radioembolization therapy (SIRT), and hepatic artery infusion (HAI). This article provides a review of pre-procedural, intra-procedural, and post-procedural aspects of each therapy, along with a review of the literature. Newer embolotherapy options and future directions are also briefly discussed.

Radioembolization, Principles and indications

Radioembolization is the selective application of radionuclide-loaded microspheres into liver arteries for the therapy of liver tumours and metastases. In this review, we focused on therapy planning and dosimetry, as well as the main indications of 90Y-glass and resin microspheres and 166Ho-microspheres.

Ytrrium-90 transarterial radioembolization in patients with gastrointestinal malignancies

Transarterial radioembolization (TARE) with yttrium-90 (Y90) is a promising alternative strategy to treat liver tumors and liver metastasis from colorectal cancer (CRC), as it selectively delivers radioactive isotopes to the tumor via the hepatic artery, sparring surrounding liver tissue. The landscape of TARE indications is constantly evolving. This strategy is considered for patients with hepatocellular carcinoma (HCC) with liver-confined disease and preserved liver function in whom neither TACE nor systemic therapy is possible. In patients with liver metastases from CRC, TARE is advised when other chemotherapeutic options have failed. Recent phase III trials have not succeeded to prove benefit in overall survival; however, it has helped to better understand the patients that may benefit from TARE based on subgroup analysis. New strategies and treatment combinations are being investigated in ongoing clinical trials. The aim of this review is to summarize the clinical applications of TARE in patients with gastrointestinal malignancies.

Liver-Directed Treatment Options Following Liver Tumor Recurrence: A Review of the Literature

Recurrence following curative-intent hepatectomy for colorectal cancer liver metastasis, hepatocellular carcinoma, or cholangiocarcinoma is unfortunately common with a reported incidence as high as 75%. Various treatment modalities can improve survival following disease recurrence. A review of the literature was performed using PubMed. In addition to systemic therapy, liver-directed treatment options for recurrent liver disease include repeat hepatectomy, salvage liver transplantation, radiofrequency or microwave ablation, intra-arterial therapy, and stereotactic body radiation therapy. Repeat resection can be consider for patients with limited recurrent disease that meets resection criteria, as this therapeutic approach can provide a survival benefit and is potentially curative in a subset of patients. Salvage liver transplantation for recurrent hepatocellular carcinoma is another option, which has been associated with a 5-year survival of 50%. Salvage transplantation may be an option in particular for patients who are not candidates for resection due to underlying liver dysfunction but meet criteria for transplantation. Ablation is another modality to treat patients who recur with smaller tumors and are not surgical candidates due to comorbidity, liver dysfunction, or tumor location. For patients with inoperable disease, transarterial chemoembolization, or radioembolization with Yttrium-90 are liver-directed intra-arterial therapy modalities with relatively low risks that can be utilized. Stereotactic body radiation therapy is another palliative treatment option that can provide a response and local tumor control for smaller tumors.

Acute Arteriobiliary Fistula Emergent Long after Biliary Drainage and Radioembolization

Various causes of hemobilia have been described in the literature, majority being iatrogenic. Other different pathologies such as inflammation and tumors also have been described. A 55-year-old male, who had a history of obstructive jaundice caused by a 4-cm liver mass treated with external-internal biliary drainage and transarterial radioembolization 6 months back, presented with acute hemobilia. Computed tomography demonstrated widespread radionecrosis of the right lobe and extravasation of intravascular contrast from right hepatic artery into common bile duct. Verified on angiography, the arteriobiliary fistula was managed with coil embolization.

Clinical application of advances and innovation in radiation treatment of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) management has evolved over the past two decades, with the development of newer treatment modalities. While various options are available, unmet needs are reflected through the mixed treatment outcome for intermediate-stage HCC. As HCC is radiosensitive, radiation therapies have a significant role in management. Radiation therapies offer local control for unresectable lesions and for patients who are not surgical candidates. Radiotherapy also provides palliation in metastatic disease, and acts as a bridge to resection and transplantation in selected patients. Advancements in radiotherapy modalities offer improved dose planning and targeted delivery, allowing for better tumor response and safer dose escalations while minimizing the risks of radiation-induced liver damage. Radiotherapy modalities are broadly classified into external beam radiation therapy and selective internal radiation therapy. With emerging modalities, radiotherapy plays a complementary role in the multidisciplinary care of HCC patients.

Aim

We aim to provide an overview of the role and clinical application of radiation therapies in HCC management.

Relevance for Patients

The continuous evolution of radiotherapy techniques allows for improved therapeutic outcomes while mitigating unwanted adverse effects, making it an attractive modality in HCC management. Rigorous clinical studies, quality research and comprehensive datasets will further its application in the present era of evidence-based practice in Medicine.

Side effects of theragnostic agents currently employed in clinical practice

Nuclear medicine plays an increasingly important role in several neoplasms management through a theragnostic approach by which targeted molecular imaging and radiotherapy are obtained with the use of radionuclide pairs with similar characteristics. In some cases, nuclear theragnostic use a pair of agents with identical chemical and biological characteristics while in others are employed theragnostic molecules which are not chemically or biologically identical but show similar biodistribution (so-called "twins in spirit" radiopharmaceuticals). This strategy was developed for the first time over 75 years ago, when iodine-131 was used for diagnostic imaging, confirmation of target expression and radionuclide therapy of thyroid cancer. Other theragnostic approaches were subsequently introduced with significant clinical results and some of them are currently considered standard treatment for different cancers. However, as any other therapy, also nuclear theragnostic treatment carries the potential risk of early deterministic and late stochastic off-target adverse effects, generally minimal and easily managed. This article reviews the reported side effects and risks of the main radiopharmaceuticals used for nuclear theragnostic in oncology for the treatment of thyroid cancer, neuroendocrine neoplasms, adrenergic tumors, metastatic prostate cancer, and liver tumors. Selecting appropriate patients using a multidisciplinary approach, meticulous pretreatment planning and knowledge of methods permit to decrease the incidence of these potential side effects.

New Kids on the Block

CONTEXT.—

With the increasing development and use of iatrogenic agents, pathologists are encountering more novel foreign materials in retrieved gastrointestinal specimens. These colorful and unusual-appearing foreign materials can pose a diagnostic dilemma to those unaware of their morphology, especially if the relevant clinical history is lacking.

OBJECTIVE.—

To discuss the histopathologic features, clinical scenarios and significance, and differential diagnosis of relatively recently described, yet quickly expanding, family of iatrogenic agents that can present as foreign materials in gastrointestinal specimens-pharmaceutical fillers (crospovidone and microcrystalline cellulose), submucosal lifting agents (Eleview and ORISE), lanthanum carbonate, hydrophilic polymers, OsmoPrep, yttrium 90 microspheres (SIR-Sphere and TheraSphere), and resins (sodium polystyrene sulfonate, sevelamer, and bile acid sequestrants).

DATA SOURCES.—

We collate the findings of published literature, including recently published research papers, and authors' personal experiences from clinical sign-out and consult cases.

CONCLUSIONS.—

Correct identification of these iatrogenic agents is important because the presence of some novel agents can explain the histopathologic findings seen in the background specimen, and specific novel agents can serve as diagnostic clues to prompt the pathologist to consider other important and related diagnoses. Awareness of even biologically inert agents is important for accurate diagnosis and to avoid unnecessary and expensive diagnostic studies.

Locoregional Therapies for Hepatocellular Carcinoma with Portal Vein Tumor Thrombosis

Hepatocellular carcinoma is the fourth leading cause of cancer worldwide, and the fastest increasing cause of cancer mortality in the United States. Its propensity for vascular invasion leads to the presence of portal vein tumor thrombus in up to half of patients. PVTT results in a classification of advanced disease, given the risk recurrence secondary to intravascular spread, and formal guidelines recommend systemic therapy in these patients. However, recent advances in locoregional therapies including TACE, TARE, and ablation have demonstrated the potential to drastically improve overall survival in patients with HCC complicated by PVTT.

Biliary-Caval Fistula following Y90 Radioembolization

The safety of radioembolization with yttrium-90 ( ⁹⁰ Y) is well documented and major complications are rare. Previous studies have demonstrated that biliary complications following ⁹⁰ Y, including bile duct injury and hepatic abscess formation, occur at an increased rate in patients who have had prior biliary surgery and interventions. This article reviews a case of a patient who developed recurrent cholangitis and sepsis as well as a biliary-caval fistula following radioembolization. Additionally, we review current data regarding biliary complications following radioembolization in patients with prior biliary intervention.

Precision Interventional Brachytherapy: A Promising Strategy Toward Treatment of Malignant Tumors

Precision interventional brachytherapy is a radiotherapy technique that combines radiation therapy medicine with computer network technology, physics, etc. It can solve the limitations of conventional brachytherapy. Radioactive drugs and their carriers change with each passing day, and major research institutions and enterprises worldwide have conducted extensive research on them. In addition, the capabilities of interventional robotic systems are also rapidly developing to meet clinical needs for the precise delivery of radiopharmaceuticals in interventional radiotherapy. This study reviews the main radiopharmaceuticals, drug carriers, dispensing and fixation technologies, and interventional robotic precision delivery systems used in precision brachytherapy of malignant tumors. We then discuss the current needs in the field and future development prospects in high-precision interventional brachytherapy.

Lung shunt fraction calculation using 99mTc-MAA SPECT/CT imaging for 90Y microsphere selective internal radiation therapy of liver tumors

BACKGROUND

^99mTc-macroaggregated albumin (^99mTc-MAA) scintigraphy is utilized in treatment planning for Yttrium-90 (⁹⁰Y) Selective Internal Radiation Therapy (SIRT) of liver tumors to evaluate hepatopulmonary shunting by calculating the lung shunt fraction (LSF). The purpose of this study was to evaluate if LSF calculation using SPECT/CT instead of planar gamma camera imaging is more accurate and if this can potentially lead to more effective treatment planning of hepatic lesions while avoiding excessive pulmonary irradiation.

RESULTS

LSF calculation was obtained using two different methodologies in 85 cases from consecutive patients intended to receive ⁹⁰Y SIRT. The first method was based on planar gamma camera imaging in the anterior and posterior views with geometric mean calculation of the LSF from regions of interest of the liver and lungs. The second method was based on segmentation of the liver and lungs from SPECT/CT images of the thorax and abdomen. The differences in planar imaging versus SPECT/CT derived LSF values along with the estimated absorbed lung mean dose (LMD) were evaluated. The LSF values were higher in planar imaging versus SPECT/CT in 81/85 cases, with a mean value of 8.5% vs. 4.6% respectively; the difference was statistically significant using a paired t-test (alpha = 0.05). In those patients who received SIRT, the estimated absorbed LMD calculated with planar imaging was significantly higher than with SPECT/CT (t-test, P < 0.005). Repeated phantom experiments using an anthropomorphic torso phantom with variable ^99mTc activity concentrations for the liver and lungs were performed with the standard patient protocol, demonstrated improved accuracy of the LSF calculation based on SPECT/CT than planar imaging (mean overestimated value of 6% vs. 26%).

CONCLUSIONS

This study demonstrates that LSF calculation using planar imaging can be significantly overestimated while calculation using SPECT/CT imaging and appropriate segmentation tools can be more accurate. Minimizing the errors in obtaining the LSF can lead to more effective ⁹⁰Y SIRT treatment planning for hepatic tumors while ensuring the lung dose will not exceed the standard acceptable safety thresholds.

Evolution of Radioembolization in Treatment of Hepatocellular Carcinoma: A Pictorial Review

Transarterial radioembolization (TARE) with yttrium 90 has increasingly been performed to treat hepatocellular carcinoma (HCC). TARE was historically used as a palliative lobar therapy for patients with advanced HCC beyond surgical options, ablation, or transarterial chemoembolization, but recent advancements have led to its application across the Barcelona Clinic Liver Cancer staging paradigm. Newer techniques, termed radiation lobectomy and radiation segmentectomy, are being performed before liver resection to facilitate hypertrophy of the future liver remnant, before liver transplant to bridge or downstage to transplant, or as a definite curative treatment. Imaging assessment of therapeutic response to TARE is challenging as the intent of TARE is to deliver local high-dose radiation to tumors through microembolic microspheres, preserving blood flow to promote radiation injury to the tumor. Because of the microembolic nature, early imaging assessment after TARE cannot rely solely on changes in size. Knowledge of the evolving methods of TARE along with the tools to assess posttreatment imaging and response is essential to optimize TARE as a therapeutic option for patients with HCC. ^©RSNA, 2021.

Pre-treatment sTNFR1 and HGF levels predict toxicity and overall survival after 90Y radioembolization: potential novel application of biomarkers for personalized management of hepatotoxicity

Liver function may be negatively affected by radiation for treatment of hepatic malignancy. Pretreatment blood cytokine levels are biomarkers for prediction of toxicity and survival after external beam radiation therapy. We hypothesized that cytokines may also predict outcomes after radioembolization, enabling a biomarker-driven personalized approach to treatment. Methods: Pre-therapy blood samples from patients enrolled on a prospective protocol evaluating ⁹⁰Y radioembolization for management of intrahepatic malignancy were analyzed for two cytokines selected based on prior studies in stereotactic body radiotherapy (SBRT), soluble tumor necrosis factor receptor 1 (sTNFR1) and hepatocyte growth factor (HGF), via enzyme-linked immunosorbent assay (ELISA), and key dosimetric parameters were derived from post-treatment ⁹⁰Y PET/CT imaging. Toxicity was defined as a change in albumin-bilirubin score (ALBI) from baseline to follow up [3-6-month post-treatment (ΔALBI)]. Associations of cytokine levels, dose metrics, and baseline liver function with toxicity and overall survival were assessed. Results: Data from 43 patients treated with ⁹⁰Y radioembolization for primary [48.8% (21/43)] or secondary [51.2% (22/43)] malignancy were assessed. Examined dose metrics and baseline liver function were not associated with liver toxicity; however, levels of sTNFR1 (P = 0.045) and HGF (P = 0.005) were associated with liver toxicity in univariate models. Cytokines were the only predictors of toxicity in multivariable models including dose metrics and prior liver directed therapy. sTNFR1 (HR 12.3; CI 3.5-42.5, p<0.001) and HGF (HR 7.5; CI 2.4-23.1, p<0.001) predicted overall survival, and findings were similar when models were controlled for absorbed dose and presence of metastatic disease. Conclusion: Pretreatment cytokine levels predict liver toxicity and overall survival. These pathways can be targeted with available drugs, an advantage over previously studied dose metrics and liver function tests. Interventions directed at the TNF alpha axis should be considered in future studies for prevention of liver toxicity, and HGF should be explored further to determine whether its elevation drives toxicity or indicates ongoing liver regeneration after prior injury.

Conventional Hepatic Volumetry May Lead to Inaccurate Segmental Yttrium-90 Radiation Dosimetry

OBJECTIVE

To compare radioembolization treatment zone volumes from mapping cone beam CT (CBCT) versus planning CT/MRI and to model their impact on dosimetry.

METHODS

Y90 cases were retrospectively identified in which intra-procedural CBCT angiograms were performed. Segmental and lobar treatment zone volumes were calculated with semi-automated contouring using Couinaud venous anatomy (planning CT/MRI) or tumor angiosome enhancement (CBCT). Differences were compared with a Wilcoxon signed-rank test. Treatment zone-specific differences in segmental volumes by volumetric method were also calculated and used to model differences in delivered dose using medical internal radiation dosimetry (MIRD) at 200 and 120 Gy targets. Anatomic, pathologic, and technical factors likely affecting segmental volumes by volumetric method were evaluated.

RESULTS

Forty segmental and 48 lobar CBCT angiograms and corresponding planning CT/MRI scans were included. Median Couinaud- and CBCT-derived segmental volumes were 281 and 243 mL, respectively (p = 0.005). Differences between Couinaud and CBCT lobar volumes (right, left) were not significant (p = 0.24, p = 0.07). Couinaud overestimated segmental volumes in 28 cases by a median of 98 mL (83%) and underestimated in 12 cases by median 69 mL (20%). At a 200 Gy dose target, Couinaud estimates produced median delivered doses of 367 and 160 Gy in these 28 and 12 cases. At a 120 Gy target, Couinaud produced doses of 220 and 96 Gy. Proximal vs. distal microcatheter positioning, variant arterial anatomy, and tumor location on or near segmental watersheds were leading factors linked to volumetric differences.

CONCLUSION

Use of CBCT-based volumetry may allow more accurate, personalized dosimetry for segmental Y90 radioembolization.

PSMA-Targeting Radiopharmaceuticals for Prostate Cancer Therapy: Recent Developments and Future Perspectives

Simple Summary

One of the most frequently diagnosed cancer in men is adenocarcinoma of the prostate. Once the disease is metastatic, only very limited treatment options are available, resulting in a very short median survival time of 13 months; however, this reality is gradually changing due to the discovery of prostate-specific membrane antigen (PSMA), a protein that is present in cancerous prostate tissue. Researchers have developed pharmaceuticals specific for PSMA, ranging from antibodies (mAb) to low-molecular weight molecules coupled to beta minus and alpha-emitting radionuclides for their use in targeted radionuclide therapy (TRT). TRT offers the possibility of selectively removing cancer tissue via the emission of radiation or radioactive particles within the tumour. In this article, the major milestones in PSMA ligand research and the therapeutic developments are summarised, together with a future perspective on the enhancement of current therapeutic approaches.

Abstract

Prostate cancer (PC) is the second most common cancer among men, with 1.3 million yearly cases worldwide. Among those cancer-afflicted men, 30% will develop metastases and some will progress into metastatic castration-resistant prostate cancer (mCRPC), which is associated with a poor prognosis and median survival time that ranges from nine to 13 months. Nevertheless, the discovery of prostate specific membrane antigen (PSMA), a marker overexpressed in the majority of prostatic cancerous tissue, revolutionised PC care. Ever since, PSMA-targeted radionuclide therapy has gained remarkable international visibility in translational oncology. Furthermore, on first clinical application, it has shown significant influence on therapeutic management and patient care in metastatic and hormone-refractory prostate cancer, a disease that previously had remained immedicable. In this article, we provide a general overview of the main milestones in the development of ligands for PSMA-targeted radionuclide therapy, ranging from the firstly developed monoclonal antibodies to the current state-of-the-art low molecular weight entities conjugated with various radionuclides, as well as potential future efforts related to PSMA-targeted radionuclide therapy.

Role of Radioembolization in the Management of Liver-Dominant Metastatic Renal Cell Carcinoma: A Single-Center, Retrospective Study

PURPOSE

The management of Renal cell carcinoma (RCC) patients with liver metastases is challenging. Liver-directed therapy, such as Transarterial radioembolization (TARE), is a reasonable option for these patients; however, its safety and efficacy are not well characterized. This study evaluated the safety and efficacy of TARE in patients with liver-dominant metastatic RCC.

MATERIALS AND METHODS

This is a retrospective, single-center study. Thirty-eight patients' medical records were reviewed who underwent TARE between January 1, 2009, and December 31, 2019, in a tertiary cancer center. Two were excluded from further analysis. Thirty-six patients received 51 TARE treatments. Median follow-up time was 18.2 months. Imaging data were evaluated using mRECIST or RECIST 1.1 criteria. Toxicities, treatment responses, liver progression-free survival (LPFS), and median overall survival (OS) were calculated. Univariate and multivariate analyses were conducted to reveal predictors of OS.

RESULTS

Median OS from TARE was 19.3 months (95% CI, 22.6-47.4) and from diagnosis of liver metastases was 36.5 months (95% CI: 26.4-49.8). Mild, grade 1 or 2, biochemical toxicity developed in 27 patients (75%). Grade 3-4 toxicity was noted in two patients (5.5%). The objective response rate was 89%; the disease control rate was 94% (21 complete response, 11 partial response, two stable disease, and two progressive disease). Univariate and multivariate analyses showed longer survival in patients who had objective response, lower lung shunt fraction, and better baseline liver function.

CONCLUSIONS

TARE is safe and effective and led to promising overall survival in patients with liver-dominant metastatic RCC.

LEVEL OF EVIDENCE

Level 3, retrospective cohort study.

Radiation segmentectomy of hepatic metastases with Y-90 glass microspheres

PURPOSE

To evaluate safety and efficacy of radiation segmentectomy (RS) with ⁹⁰Y glass microspheres in patients with limited metastatic liver disease not amenable to resection or percutaneous ablation.

METHODS

Patients with ≤ 3 tumors treated with RS from 6/2015 to 12/2017 were included. Target tumor radiation dose was > 190 Gy based on medical internal radiation dose (MIRD) dosimetry. Tumor response, local tumor progression (LTP), LTP-free survival (LTPFS) and disease progression rate in the treated segment were defined using Choi and RECIST 1.1 criteria. Toxicities were evaluated using modified SIR criteria.

RESULTS

Ten patients with 14 tumors underwent 12 RS. Median tumor size was 3 cm (range 1.4-5.6). Median follow-up was 17.8 months (range 1.6-37.3). Response rates per Choi and RECIST 1.1 criteria were 8/8 (100%) and 4/9 (44%), respectively. Overall LTP rate was 3/14 (21%) during the study period. One-, two- and three-year LTPFS was 83%, 83% and 69%, respectively. Median LTPFS was not reached. Disease progression rate in the treated segment was 6/18 (33%). Median overall survival was 41.5 months (IQR 16.7-41.5). Median delivered tumor radiation dose was 293 Gy (range 163-1303). One major complication was recorded in a patient post-Whipple procedure who suffered anaphylactic reaction to prophylactic cefotetan and liver abscess in RS region 6.5 months post-RS. All patients were alive on last follow-up.

CONCLUSION

RS of ≤ 3 hepatic segments can safely provide a 2-year local tumor control rate of 83% in selected patients with limited metastatic liver disease and limited treatment options. Optimal dosimetry methodology requires further investigation.

Does significantly elevated lung shunt fraction (LSF >20%) promote extrahepatic progression in patients with hepatocellular carcinoma treated with radioembolization?

PURPOSE

Radioembolization with yttrium-90 (Y-90) is an effective locoregional therapy for primary and metastatic liver tumors, but its use is restricted or contraindicated for patients with elevated lung shunt fraction (LSF) because of an increased risk of developing pulmonary adverse events, including but not limited to radiation pneumonitis. Elevated LSF is also thought to be correlated with liver tumor progression and metastases.

METHODS

In this retrospective cohort study, we examine rates of metastasis development, rates of adverse events and overall survival (OS) in 23 patients with hepatocellular carcinoma (HCC) and elevated LSF >20% on Tc-99 m macroaggregated albumin scan treated with Y-90 radioembolization at our institution from 2005 to 2016. To minimize confounding variables, patients with baseline extrahepatic metastases or portal vein tumor thrombosis were excluded. Kaplan-Meier estimates were performed for OS and time to development of metastases.

RESULTS

No patient developed clinical and imaging signs of radiation pneumonitis. Median intention to treat OS from day of radioembolization was 21.3 months; median censored OS was 14.7 months. Five out of 23 patients (22%) developed at least one metastasis during follow-up, for an incidence of 20 per 1000 patient-years (compared to the historical rate of 6 per 1000 patient-years for HCC patients in general).

CONCLUSION

HCC patients with LSF >20% treated with Y-90 radioembolization have acceptable toxicities and appear to have a rate of extrahepatic tumor development (22%) higher than expected for patients with HCC.

Microspheres Used in Liver Radioembolization: From Conception to Clinical Effects

Inert microspheres, labeled with several radionuclides, have been developed during the last two decades for the intra-arterial treatment of liver tumors, generally called Selective Intrahepatic radiotherapy (SIRT). The aim is to embolize microspheres into the hepatic capillaries, accessible through the hepatic artery, to deliver high levels of local radiation to primary (such as hepatocarcinoma, HCC) or secondary (metastases from several primary cancers, e.g., colorectal, melanoma, neuro-endocrine tumors) liver tumors. Several types of microspheres were designed as medical devices, using different vehicles (glass, resin, poly-lactic acid) and labeled with different radionuclides, 90Y and 166Ho. The relationship between the microspheres' properties and the internal dosimetry parameters have been well studied over the last decade. This includes data derived from the clinics, but also computational data with various millimetric dosimetry and radiobiology models. The main purpose of this paper is to define the characteristics of these radiolabeled microspheres and explain their association with the microsphere distribution in the tissues and with the clinical efficacy and toxicity. This review focuses on avenues to follow in the future to optimize such particle therapy and benefit to patients.

Evaluation of different CT maps for attenuation correction and segmentation in static 99m Tc-MAA SPECT/CT for 90 Y radioembolization treatment planning: A simulation study

PURPOSE

Conventional ^99m Tc-macroaggregated albumin (^99m Tc-MAA) planar scintigraphy overestimates lung shunt fraction (LSF) compared to SPECT/CT. However, the respiratory motion artifact due to the temporal mismatch between static SPECT and helical CT (HCT) may compromise the SPECT quantitation accuracy by incorrect attenuation correction (AC) and volume-of-interest (VOI) segmentation. This study aims to evaluate AC and VOI segmentation effects systematically and to propose a CT map for LSF and tumor-to-normal liver ratio (TNR) estimation in static ^99m Tc-MAA SPECT/CT.

METHODS

The 4D XCAT phantom was used to simulate a phantom population of 120 phantoms, modeling 10 different anatomical variations, nine TNRs (2-13.2), nine tumor sizes (2-6.7 cm diameter), eight tumor locations, three axial motion amplitudes of 1, 1.5, and 2 (cm), and four LSFs of 5%, 10%, 15%, and 20%. An analytical projector for low-energy high-resolution parallel-hole collimator was used to simulate 60 noisy projections over 360°, modeling attenuation and geometric collimator-detector response (GCDR). AC and VOI mismatch effects were investigated independently and together, using cine average CT (CACT), HCT at end-inspiration (HCT-IN), mid-respiration (HCT-MID), and end-expiration (HCT-EX) respectively as attenuation and segmentation maps. SPECT images without motion, AC, and VOI errors were also generated as reference. LSF and TNR errors were measured as compared to the ground truth.

RESULTS

HCT-MID has slightly better performance for AC effect compared with other CT maps in LSF and TNR estimation, while HCT-EX and HCT-MID perform better for VOI effect. For a respiratory motion amplitude of 1.5 cm and a LSF of 5%, the LSF errors are 19.56 ± 4.58%, -6.79 ± 1.74%, 77.29 ± 14.74%, and 111.25 ± 18.29% corresponding to HCT-MID, HCT-EX, HCT-IN, and CACT in static SPECT. The TNR errors are -12.38 ± 6.42%, -20.55 ± 11.25%, -20.89 ± 9.98%, and -22.89 ± 14.38% respectively. HCT-MID has the best performance for LSF estimation for LSF > 10% and TNR estimation, followed by HCT-EX, HCT-IN, and CACT.

CONCLUSIONS

The HCT-MID is recommended for AC and segmentation to alleviate respiratory artifacts and improve quantitation accuracy in ⁹⁰ Y radioembolization treatment planning. HCT-EX would also be a recommended choice if HCT-MID is not available.

Liposome technologies towards colorectal cancer therapeutics

Colorectal cancer (CRC) is the third most common cancer and the fourth most common deadly cancer worldwide. After treatment with curative intent recurrence rates vary with staging 0-13% in Stage 1, 11-61% in S2 and 28-73% in Stage 3. The toxicity to healthy tissues from chemotherapy and radiotherapy and drug resistance severely affect the quality of life and cancer specific outcomes of CRC patients. To overcome some of these limitations, many efforts have been made to develop nanomaterial-based drug delivery systems. Among these nanocarriers, liposomes represented one of the most successful candidates in delivering targeted oncological treatment, improving safety profile and therapeutic efficacy of encapsulated drugs. In this review we will discuss liposome design with a particular focus on the targeting feature and triggering functions. We will also summarise the recent advances in liposomal delivery system for CRC treatment in both the preclinical and clinical studies. We will finally provide our perspectives on the liposome technology development for the future clinical translation. STATEMENT OF SIGNIFICANCE: Conventional treatments for colorectal cancer (CRC) severely affect the therapeutic effects for advanced patients. With the development of nanomedicines, liposomal delivery system appears to be one of the most promising nanocarriers for CRC treatment. In last three years several reviews in this area have been published focusing on the preclinical research and drug delivery function, which is a fairly narrow focus in the field of liposome technology for CRC therapy. Our review presented the most recent advances of the liposome technology (both clinical and preclinical applications) for CRC with strong potential for further clinical translation. We believe it will attract lots of attention from various audiences, including researchers, clinicians and the industry.

Hepatocellular Carcinoma: Downstaging to Liver Transplantation as Curative Therapy

Hepatocellular carcinoma (HCC) ranks among the leading cancer-related causes of morbidity and mortality worldwide. Downstaging of HCC has prevailed as a key method to curative therapy for patients who present with unresectable HCC outside of the listing criteria for liver transplantation (LT). Even though LT paves the way to lifesaving curative therapy for HCC, perpetually severe organ shortage limits its broader application. Debate over the optimal protocol and assessment of response to downstaging treatment has fueled immense research activity and is pushing the boundaries of LT candidate selection criteria. The implicit obligation of refining downstaging protocol is to ensure the maximization of the transplant survival benefit by taking into account the waitlist life expectancy. In the following review, we critically discuss strategies to best optimize downstaging HCC to LT on the basis of existing literature.