Safety and initial efficacy of radiation segmentectomy for the treatment of hepatic metastases​

Histopathologic Changes after Yttrium-90 Radioembolization of Colorectal Liver Metastases: A Pilot Feasibility Study

PURPOSE

To evaluate the histopathologic changes and potential correlations of tumor absorbed dose (TAD) after yttrium-90 transarterial radioembolization (TARE) for colorectal liver metastases (CLMs).

MATERIALS AND METHODS

This prospective pilot study assessed 12 patients with 13 CLMs through positron emission tomography (PET)/computed tomography (CT)-guided biopsies before, immediately after TARE (T0), and 3 weeks after TARE (T3). Subsequent sampling from the same location was enabled by fiducial placement. Biopsy samples were evaluated with hematoxylin and eosin, TUNEL, Ki67, OxPhos, caspase-3 (CC3), and pH2AX antibodies. Proliferation changes (Ki67) and double-strand DNA breaks (DSBs) were evaluated quantitatively. TAD was calculated on post-TARE PET/CT scan of the biopsy needle location at T0 and T3.

RESULTS

Median TAD at 3 weeks after TARE was 162 Gy (interquartile range (IQR), 92-211 Gy). DSBs decreased significantly from T0 (median, 77%; IQR, 75%-100%) to T3 (median, 14%; IQR, 0%-54%; P = .028). A decrease in Ki67 was also documented (median, 73%; IQR, 70%-80% at T0 vs median, 41%; IQR, 0%-66% at T3; P = .046). There was a strong positive correlation between TAD and DSBs at T0 (r[9] = 0.68) and a strong negative correlation at T3 (r[10] = -0.855; P = .042 and P = .002, respectively). There was a strong negative correlation between TAD and Ki67 at both T0 (r[9] = -0.733; P = .025) and T3 (r[10] = -0.681; P = .030). Tumors that exhibited caspase-3 activation (8/13, 62%) at either T0 or T3 time point were more likely to develop progression (7/8 [88%] vs 1/5 [20%]; P = .015).

CONCLUSIONS

Post-TARE biopsy can be used to assess TAD and histopathologic changes. Significant decreases in DSBs and proliferation index were noted after TARE. Post-TARE CC3 activation deserves further exploration.

Recommendations for the management of yttrium-90 radioembolization in the treatment of patients with colorectal cancer liver metastases: a multidisciplinary review

PURPOSE

Strategies for the treatment of liver metastases from colon cancer (lmCRC) are constantly evolving. Radioembolization with yttrium 90 (Y-90 TARE) has made significant advancements in treating liver tumors and is now considered a potential option allowing for future resection. This study reviewed the scientific evidence and developed recommendations for using Y-90 TARE as a treatment strategy for patients with unresectable lmCRC.

METHODS

A multidisciplinary scientific committee, consisting of experts in medical oncology, hepatobiliary surgery, radiology, and nuclear medicine, all with extensive experience in treating patients with ImCRC with Y-90 TARE, led this project. The committee established the criteria for conducting a comprehensive literature review on Y-90 TARE in the treatment of lmCRC. The data extraction process involved addressing initial preliminary inquiries, which were consolidated into a final set of questions.

RESULTS

This review offers recommendations for treating patients with lmCRC using Y-90 TARE, addressing four areas covering ten common questions: 1) General issues (multidisciplinary tumor committee, indications for treatment, contraindications); 2) Previous process (predictive biomarkers for patient selection, preintervention tests, published evidence); 3) Procedure (standard procedure); and 4) Post-intervention follow-up (potential toxicity and its management, parameters for evaluation, quality of life).

CONCLUSIONS

Based on the insights of the multidisciplinary committee, this document offers a comprehensive overview of the technical aspects involved in the management of Y-90 TARE. It synthesizes recommendations for applying Y-90 TARE across various phases of the treatment process.

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.

Yttrium-90 Activity Quantification in PET/CT-Guided Biopsy Specimens from Colorectal Hepatic Metastases Immediately after Transarterial Radioembolization Using Micro-CT and Autoradiography

PURPOSE

To evaluate the yttrium-90 (90Y) activity distribution in biopsy tissue samples of the treated liver to quantify the dose with higher spatial resolution than positron emission tomography (PET) for accurate investigation of correlations with microscopic biological effects and to evaluate the radiation safety of this procedure.

MATERIALS AND METHODS

Eighty-six core biopsy specimens were obtained from 18 colorectal liver metastases (CLMs) immediately after 90Y transarterial radioembolization (TARE) with either resin or glass microspheres using real-time 90Y PET/CT guidance in 17 patients. A high-resolution micro-computed tomography (micro-CT) scanner was used to image the microspheres in part of the specimens and allow quantification of 90Y activity directly or by calibrating autoradiography (ARG) images. The mean doses to the specimens were derived from the measured specimens' activity concentrations and from the PET/CT scan at the location of the biopsy needle tip for all cases. Staff exposures were monitored.

RESULTS

The mean measured 90Y activity concentration in the CLM specimens at time of infusion was 2.4 ± 4.0 MBq/mL. The biopsies revealed higher activity heterogeneity than PET. Radiation exposure to the interventional radiologists during post-TARE biopsy procedures was minimal.

CONCLUSIONS

Counting the microspheres and measuring the activity in biopsy specimens obtained after TARE are safe and feasible and can be used to determine the administered activity and its distribution in the treated and biopsied liver tissue with high spatial resolution. Complementing 90Y PET/CT imaging with this approach promises to yield more accurate direct correlation of histopathological changes and absorbed dose in the examined specimens.

Interventional radiological therapies in colorectal hepatic metastases

Colorectal malignancy is the third most common cancer and one of the prevalent causes of death globally. Around 20-25% of patients present with metastases at the time of diagnosis, and 50-60% of patients develop metastases in due course of the disease. Liver, followed by lung and lymph nodes, are the most common sites of colorectal cancer metastases. In such patients, the 5-year survival rate is approximately 19.2%. Although surgical resection is the primary mode of managing colorectal cancer metastases, only 10-25% of patients are competent for curative therapy. Hepatic insufficiency may be the aftermath of extensive surgical hepatectomy. Hence formal assessment of future liver remnant volume (FLR) is imperative prior to surgery to prevent hepatic failure. The evolution of minimally invasive interventional radiological techniques has enhanced the treatment algorithm of patients with colorectal cancer metastases. Studies have demonstrated that these techniques may address the limitations of curative resection, such as insufficient FLR, bi-lobar disease, and patients at higher risk for surgery. This review focuses on curative and palliative role through procedures including portal vein embolization, radioembolization, and ablation. Alongside, we deliberate various studies on conventional chemoembolization and chemoembolization with irinotecan-loaded drug-eluting beads. The radioembolization with Yttrium-90 microspheres has evolved as salvage therapy in surgically unresectable and chemo-resistant metastases.

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.

EANM procedure guideline for the treatment of liver cancer and liver metastases with intra-arterial radioactive compounds

Primary liver tumours (i.e. hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICC)) are among the most frequent cancers worldwide. However, only 10-20% of patients are amenable to curative treatment, such as resection or transplant. Liver metastases are most frequently caused by colorectal cancer, which accounts for the second most cancer-related deaths in Europe. In both primary and secondary tumours, radioembolization has been shown to be a safe and effective treatment option. The vast potential of personalized dosimetry has also been shown, resulting in markedly increased response rates and overall survival. In a rapidly evolving therapeutic landscape, the role of radioembolization will be subject to changes. Therefore, the decision for radioembolization should be taken by a multidisciplinary tumour board in accordance with the current clinical guidelines. The purpose of this procedure guideline is to assist the nuclear medicine physician in treating and managing patients undergoing radioembolization treatment. PREAMBLE: The European Association of Nuclear Medicine (EANM) is a professional non-profit medical association that facilitates communication worldwide among individuals pursuing clinical and research excellence in nuclear medicine. The EANM was founded in 1985. These guidelines are intended to assist practitioners in providing appropriate nuclear medicine care for patients. They are not inflexible rules or requirements of practice and are not intended, nor should they be used, to establish a legal standard of care. The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by medical professionals taking into account the unique circumstances of each case. Thus, there is no implication that an approach differing from the guidelines, standing alone, is below the standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set out in the guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources or advances in knowledge or technology subsequent to publication of the guidelines. The practice of medicine involves not only the science but also the art of dealing with the prevention, diagnosis, alleviation and treatment of disease. The variety and complexity of human conditions make it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment. Therefore, it should be recognised that adherence to these guidelines will not ensure an accurate diagnosis or a successful outcome. All that should be expected is that the practitioner will follow a reasonable course of action based on current knowledge, available resources and the needs of the patient to deliver effective and safe medical care. The sole purpose of these guidelines is to assist practitioners in achieving this objective.

The Role of Ablative Radiotherapy to Liver Oligometastases from Colorectal Cancer

Purpose of Review

This review describes recent data supporting locoregional ablative radiation in the treatment of oligometastatic colorectal cancer liver metastases.

Recent Findings

Stereotactic body radiotherapy (SBRT) demonstrates high rates of local control in colorectal cancer liver metastases when a biologically equivalent dose of > 100 Gy is delivered. Future innovations to improve the efficacy of SBRT include MRI-guided radiotherapy (MRgRT) to enhance target accuracy, systemic immune activation to treat extrahepatic disease, and genomic customization. Selective internal radiotherapy (SIRT) with y-90 is an intra-arterial therapy that delivers high doses to liver metastases internally which has shown to increase liver disease control in phase 3 trials. Advancements in transarterial radioembolization (TARE) dosimetry could improve local control and decrease toxicity.

Summary

SBRT and SIRT are both promising options in treating unresectable metastatic colorectal cancer liver metastases. Identification of oligometastatic patients who receive long-term disease control from either therapy is essential. Future advancements focusing on improving radiation design and customization could further improve efficacy and toxicity.

Biomarkers associated with survival and favourable outcome of radioembolization with yttrium-90 glass microspheres for colon cancer liver metastases: Single centre experience

OBJECTIVE

To determine the therapeutic effectiveness and safety of transarterial radioembolization (TARE) with Yttrium-90 in patients with colorectal cancer (CRC) liver metastases and to evaluate the prognostic value of different biomarkers.

MATERIAL AND METHODS

This prospective longitudinal study enrolled consecutive patients with CRC liver metastases treated with TARE between November 2015 and june 2020. The therapeutic response at three and six months (RECIST1.1 criteria) and the relationship of biomarkers with therapeutic response, by calculating objective tumor response rates (ORR) and disease control (DCR), and overall survival (OS) and progression-free (PFS).

RESULTS

Thirty TAREs were performed in 23 patients (mean age, 61.61 ± 9.13 years; 56.5% male). At three months, the objective response rate (ORR) was 16.7% and the disease control rate (DCR) 53.3%. At six months, the disease progressed in 80%. The ORR and DCR were significantly associated with age at diagnosis (P = 0.047), previous bevacizumab treatment (P = 0.008), pre-TARE haemoglobin (P = 0.008), NLR (P = 0.040), pre-TARE albumin (P = 0.012), pre-TARE ALT (P = 0.023) and tumour-absorbed dose > 115 Gy (P = 0.033). Median overall survival (OS) was 12 months (95% CI, 4.75-19.25 months) and median progression-free survival (PFS) 3 months (95% CI, 2.41-3.59). OS was significantly associated with primary tumour resection (P = 0.019), KRAS mutation (HR: 5.15; P = 0.024), pre-TARE haemoglobin (HR: 0.50; p = 0.009), pre-TARE NLR (HR: 1.65; P = 0.005) and PLR (HR: 1.01; P = 0.042).

CONCLUSION

TARE prognosis and therapeutic response were predicted by different biomarkers, ranging from biochemical parameters to tumour dosimetrics.

Biomarkers associated with survival and favourable outcome of radioembolization with yttrium-90 glass microspheres for colon cancer liver metastases: Single centre experience

OBJETIVE

To determine the therapeutic effectiveness and safety of transarterial radioembolization (TARE) with Yttrium-90 in patients with colorectal cancer (CRC) liver metastases and to evaluate the prognostic value of different biomarkers.

MATERIAL AND METHODS

This prospective longitudinal study enrolled consecutive patients with CRC liver metastases treated with TARE between November 2015 and june 2020. The therapeutic response at three and six months (RECIST1.1 criteria) and the relationship of biomarkers with therapeutic response, by calculating objective tumor response rates (ORR) and disease control (DCR), and overall survival (OS) and progression-free (PFS).

RESULTS

Thirty TAREs were performed in 23 patients (mean age, 61,61±9,13 years; 56,5% male). At three months, the objective response rate (ORR) was 16,7% and the disease control rate (DCR) 53,3%. At six months, the disease progressed in 80%. The ORR and DCR were significantly associated with age at diagnosis (P=.047), previous bevacizumab treatment (P=.008), pre-TARE haemoglobin (P=.008), NLR (P=.040), pre-TARE albumin (P=.012), pre-TARE ALT (P=.023) and tumour-absorbed dose>115Gy (P=.033). Median overall survival (OS) was 12 months (95% CI, 4.75-19.25 months) and median progression-free survival (PFS) 3 months (95% CI, 2.41-3.59). OS was significantly associated with primary tumour resection (P=.019), KRAS mutation (HR: 5.15; P=.024), pre-TARE haemoglobin (HR: .50; p=.009), pre-TARE NLR (HR: 1.65; P=.005) and PLR (HR: 1.01; P=.042).

CONCLUSION

TARE prognosis and therapeutic response were predicted by different biomarkers, ranging from biochemical parameters to tumour dosimetrics.

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.

Review of Intra-Arterial Therapies for Colorectal Cancer Liver Metastasis

Simple Summary

Colorectal cancer liver metastasis occurs in more than 50% of patients with colorectal cancer and is thought to be the most common cause of death from this cancer. The mainstay of treatment for inoperable liver metastasis has been combination systemic chemotherapy with or without the addition of biological targeted therapy with a goal for disease downstaging, for potential curative resection, or more frequently, for disease control. For patients with dominant liver metastatic disease or limited extrahepatic disease, liver-directed intra-arterial therapies including hepatic arterial chemotherapy infusion, chemoembolization and radioembolization are alternative treatment strategies that have shown promising results, most commonly in the salvage setting in patients with chemo-refractory disease. In recent years, their role in the first-line setting in conjunction with concurrent systemic chemotherapy has also been explored. This review aims to provide an update on the current evidence regarding liver-directed intra-arterial treatment strategies and to discuss potential trends for the future.

Abstract

The liver is frequently the most common site of metastasis in patients with colorectal cancer, occurring in more than 50% of patients. While surgical resection remains the only potential curative option, it is only eligible in 15–20% of patients at presentation. In the past two decades, major advances in modern chemotherapy and personalized biological agents have improved overall survival in patients with unresectable liver metastasis. For patients with dominant liver metastatic disease or limited extrahepatic disease, liver-directed intra-arterial therapies such as hepatic arterial chemotherapy infusion, chemoembolization and radioembolization are treatment strategies which are increasingly being considered to improve local tumor response and to reduce systemic side effects. Currently, these therapies are mostly used in the salvage setting in patients with chemo-refractory disease. However, their use in the first-line setting in conjunction with systemic chemotherapy as well as to a lesser degree, in a neoadjuvant setting, for downstaging to resection have also been investigated. Furthermore, some clinicians have considered these therapies as a temporizing tool for local disease control in patients undergoing a chemotherapy ‘holiday’ or acting as a bridge in patients between different lines of systemic treatment. This review aims to provide an update on the current evidence regarding liver-directed intra-arterial treatment strategies and to discuss potential trends for the future.

Interventional Oncology Approach to Hepatic Metastases

Metastatic liver disease is one of the major causes of cancer-related morbidity and mortality. Locoregional therapies offered by interventional oncologists alleviate cancer-related morbidity and in some cases improve survival. Locoregional therapies are often palliative in nature but occasionally can be used with curative intent. This review will discuss important factors to consider prior to palliative and curative intent treatment of metastatic liver disease with locoregional therapy. These factors include those specific to the tumor, liver function, liver reserve, differences between treatment modalities, and patient-specific considerations.

Yttrium-90 radiation segmentectomy for hepatic metastases: A multi-institutional study of safety and efficacy

BACKGROUND AND OBJECTIVES

This study assessed the outcomes of Yttrium-90 (⁹⁰ Y) radiation segmentectomy for hepatic metastases unamenable to resection or ablation.

MATERIALS AND METHODS

Over 6 years, 36 patients with 53 tumors underwent segmental radioembolization. Patients were not candidates for surgical resection or thermal ablation. Malignancies included metastases from colorectal cancer (31%), neuroendocrine tumors (28%), sarcoma (19%), and others (22%). Eighty-one percent of patients had undergone prior treatment with systemic chemotherapy. Ongoing systemic chemotherapy was continued. Toxicity, tumor response, tumor progression, and survival were assessed.

RESULTS

The median tumor size was 3.6 cm (range 1.2-6.1 cm). Adverse event rates were low, with no hepatic-related Common Terminology Criteria for Adverse Events Grade 3 or 4 toxicity. Target tumor Response Evaluation Criteria in Solid Tumors disease control rate was 92% (28% partial response, 64% stable disease). For patients with enhancing tumors (n = 14), modified Response Evaluation Criteria in Solid Tumors target tumor objective response rate was 100%. During a median follow-up of 12 months, target tumor progression occurred in 28% of treated tumors. Overall survival was 96% and 83% at 6 and 12 months, respectively.

CONCLUSIONS

⁹⁰ Y radiation segmentectomy for hepatic metastases demonstrates high rates of tumor control and minimal toxicity. Radiation segmentectomy should be considered for patients with metastatic hepatic malignancy who are not candidates for surgical resection.

Preparation and characterization of inorganic radioactive holmium-166 microspheres for internal radionuclide therapy

Microspheres with high specific activities of radionuclides are very interesting for internal radiotherapy treatments. This work focuses on the formulation and characterization of inorganic microspheres with a high content of holmium and therefore a high specific radioactivity of holmium-166. Two novel formulations of inorganic microspheres were obtained by dispersing solid holmium acetylacetonate microspheres (Ho₂(AcAc)₃-ms) in NaH₂PO₄ or NaOH solutions followed by 2 h incubation at room temperature. By exchange of acetylacetonate with phosphate or hydroxyl ions, holmium phosphate microspheres (HoPO₄-ms) and holmium hydroxide microspheres (Ho(OH)₃-ms) were formed respectively. The inorganic microspheres had a significantly smaller diameter (28.5 ± 4.4 μm (HoPO₄-ms) and 25.1 ± 3.5 μm (Ho(OH)₃-ms)) than those of Ho₂(AcAc)₃-ms (32.6 ± 5.2 μm). The weight percentage of holmium-165 in the microspheres increased significantly from 47% (Ho₂(AcAc)₃-ms) to 55% (HoPO₄-ms) and 73% (Ho(OH)₃-ms). After preparation of both HoPO₄-ms and Ho(OH)₃-ms, the stable holmium-165 isotope was partly converted by neutron activation into radioactive holmium-166 to yield radioactive microspheres. High specific activities were achieved ranging from 21.7 to 59.9 MBq/mg (¹⁶⁶HoPO₄-ms) and from 28.8 to 79.9 MBq/mg (¹⁶⁶Ho(OH)₃-ms) depending on the neutron activation time. The structure of both microspheres was preserved up to neutron activations of 6 h in a thermal neutron flux of 4.72 × 10¹⁶ n m^-2 s^-1. After activation, both microspheres revealed excellent stability in administration fluids (saline and phosphate buffer) having less than 0.05% of holmium released after 72 h incubation. Finally, the hemocompatibility of these inorganic microspheres was evaluated and it was shown that the microspheres did cause neither hemolysis nor depletion or inhibition of the coagulation factors of the intrinsic blood coagulation pathway meaning that the microspheres have a good hemocompatibility. Overall, this work shows that radioactive inorganic microspheres with high specific activities of holmium-166 can be prepared which potentially can be used for internal radionuclide therapy.

Radiation segmentectomy for hepatic malignancies: Indications, devices, dosimetry, procedure, clinical outcomes, and toxicity of yttrium-90 microspheres

Radiation segmentectomy (RS) is a new approach to ⁹⁰Y radioembolization that has been designed to increase the safety and efficacy of radioembolization in patients with unresectable hepatic malignancies. With this technique, high doses (>190 Gy) of radiation are delivered to the tumor through radioembolization performed in a segmental fashion, potentially increasing the radiation dose to the tumor while minimizing injury to the liver parenchyma. The aim of this review is to provide a summary of the indications, device choice, dosimetry, procedure, clinical outcomes, and toxicity of RS based on the clinical series currently available.

Y90 Radioembolization Dosimetry: Concepts for the Interventional Radiologist

Transarterial radioembolization (TARE) with beta particle emitting microspheres via Yttrium-90 decay has become a fundamental component of the contemporary Interventional Oncology practice. TARE continues to advance as a result of increased utilization, clinical study, technological improvements, and evolving applications. To maximize TARE safety and efficacy, a core understanding of dosimetry is essential. The intent of this overview is to provide the reader with a general survey of radiation physics and biology, device differentiation, patient selection, anatomic assessment, activity administration models, and procedural techniques involved with TARE dosimetry.