Radioembolization with 90Y Resin Microspheres of Neuroendocrine Liver Metastases After Initial Peptide Receptor Radionuclide Therapy

Multidisciplinary Delphi Consensus on Safety of Combining Transarterial Radioembolization with Yttrium-90 Microspheres with Systemic Anticancer Agents for the Treatment of Liver Malignancy

PURPOSE

To provide guidance, via multidisciplinary consensus statements, on the safety interactions between systemic anticancer agents (such as radiosensitizing chemotherapy, immunotherapy, targeted therapy, and peptide receptor radionuclide therapy) and transarterial radioembolization (TARE) with yttrium-90 (90Y)-labeled microspheres in the treatment of primary and metastatic liver malignancies.

MATERIALS AND METHODS

A literature search identified 59 references that informed 26 statements on the safety of 90Y TARE combined with systemic therapies. Modified Delphi method was used to develop consensus on statements through online anonymous surveys of the 12 panel members representing the fields of interventional radiology, medical oncology, surgical oncology, hepatology, and pharmacy, focusing on hepatocellular carcinoma (HCC), metastatic colorectal cancer (mCRC), neuroendocrine tumors, metastatic breast cancer, and intrahepatic cholangiocarcinoma.

RESULTS

High-level evidence was limited. Level 1 data in patients with mCRC suggest that some radiosensitizing chemotherapies (eg, oxaliplatin) require temporary dose reduction when used concomitantly with 90Y TARE, and some targeted therapies (eg, vascular endothelial growth factor inhibitors and antiangiogenic tyrosine kinase inhibitors) should be avoided for at least 4 weeks before 90Y TARE. In patients with HCC, the feasibility of 90Y TARE and immunotherapy has been demonstrated with Level 4 evidence. Data are more limited for other primary and secondary liver malignancies, and consensus statements were driven by expert opinion (Level 5).

CONCLUSIONS

Given the absence of evidence-based guidelines on the safety of 90Y TARE in combination with systemic anticancer therapy, these consensus statements provide expert guidance on the potential risks when considering specific combinations.

[Nuclear medicine approaches in the diagnosis and treatment of neuroendocrine neoplasms]

Despite, or perhaps because of the rarity of neuroendocrine neoplasms, the diagnosis and treatment of these malignancies is of particular importance. Nuclear medicine can make an important contribution to this challenge. It offers the most sensitive and specific imaging of these tumor entities and can be helpful in treatment due to the radiotherapeutic drugs that have recently been approved. This theragnostic (fusion of therapeutic and diagnostic) concept is based on the frequent overexpression of somatostatin receptors on neuroendocrine tumor cells.Using diagnostic and therapeutic pharmaceuticals based on analogues from somatostatin, most applications from the nuclear medicine are successful, an additional therapeutic method is SIRT, also known as TARE, in which the hypervascularization of NEN-metastases is used as a therapeutic target.

Safety and Efficacy of Peptide Receptor Radionuclide Therapy (PRRT) Following Bland Embolization for Metastatic Neuroendocrine Tumors

Rationale: Evaluating the long-term safety and efficacy of peptide receptor radionuclide therapy (PRRT) in patients with metastatic neuroendocrine tumors (mNETs) who have undergone prior bland hepatic transarterial embolization (TAE). Methods: Retrospective review of mNET patients who received PRRT with 177Lu-DOTATATE between 4/2018 and 02/2022 with and without prior TAE. The most recent clinical, imaging, and laboratory findings, including hepatic Common Terminology Criteria for Adverse Events v5.0, were compared to pre-PRRT. Results: 171 patients (95 M, 76 F, median age = 66) with mNET of different primary sites (9 foregut, 100 midgut, 9 hindgut, 44 pancreas, 9 unknown) received at least 1 cycle of PRRT with at least 6 months of follow-up, 110 of whom were embolization-naïve and 61 who had prior TAE. The median follow up was 22 months (range: 6-43). Patients with prior TAE had higher liver tumor burden on average than patients without prior TAE; however, the difference was not statistically significant (p = 0.06). There was no significant difference in the rates of G3 or G4 hepatotoxicity (p = 0.548 and p = 0.999, respectively) in patients who underwent prior TAE and those who were TAE-naïve. The hepatic progression-free survival was 22.9 months in TAE-naïve patients and 25.7, 20.2, and 12.8 months in patients with 1, 2, and 3 prior TAE treatments, respectively. Conclusion: Peptide receptor radionuclide therapy following transarterial bland embolization for mNET is safe and effective.

Liver Imaging in Gastroenteropancreatic Neuroendocrine Neoplasms

ABSTRACT

The incidence of neuroendocrine neoplasms (NENs) has gradually increased over the past few decades with the majority of patients presenting with metastases on initial presentation. The liver is the most common site of initial metastatic disease, and the presence of liver metastasis is an independent prognostic factor associated with a negative outcome. Because NENs are heterogenous neoplasms with variable differentiation, grading, and risk of grade transformation over time, accurate diagnosis and management of neuroendocrine liver lesions are both important and challenging. This is particularly so with the multiple liver-directed treatment options available. In this review article, we discuss the diagnosis, treatment, and response evaluation of NEN liver metastases.

Hepatic Radioembolization: A Multistep Theragnostic Procedure

This article provides a thorough overview of the practice and multistep approach of hepatic radioembolization. The current literature on hepatic radioembolization in primary or metastatic liver tumors as well as future perspectives are discussed.

Liver-Directed Locoregional Therapies for Neuroendocrine Liver Metastases: Recent Advances and Management

Neuroendocrine tumors (NETs) are a heterogeneous class of cancers, predominately occurring in the gastroenteropancreatic system, which pose a growing health concern with a significant rise in incidence over the past four decades. Emerging from neuroendocrine cells, these tumors often elicit paraneoplastic syndromes such as carcinoid syndrome, which can manifest as a constellation of symptoms significantly impacting patients' quality of life. The prognosis of NETs is influenced by their tendency for metastasis, especially in cases involving the liver, where the estimated 5-year survival is between 20 and 40%. Although surgical resection remains the preferred curative option, challenges emerge in cases of neuroendocrine tumors with liver metastasis (NELM) with multifocal lobar involvement, and many patients may not meet the criteria for surgery. Thus, minimally invasive and non-surgical treatments, such as locoregional therapies, have surfaced. Overall, these approaches aim to prioritize symptom relief and aid in overall tumor control. This review examines locoregional therapies, encompassing catheter-driven procedures, ablative techniques, and radioembolization therapies. These interventions play a pivotal role in enhancing progression-free survival and managing hormonal symptoms, contributing to the dynamic landscape of evolving NELM treatment. This review meticulously explores each modality, presenting the current state of the literature on their utilization and efficacy in addressing NELM.

Liver-Directed Therapy for Neuroendocrine Tumor Metastases in the Era of Peptide Receptor Radionuclide Therapy

OPINION STATEMENT

The treatment of neuroendocrine neoplasm (NEN) liver metastases involves a multidisciplinary approach that includes liver-directed therapies (LDT) and systemic treatments, such as peptide receptor radionuclide therapy (PRRT). LDT has demonstrated efficacy in rapidly reducing tumor bulk, improving symptoms, and delaying disease progression. Interventional radiologists should be consulted prior to switching therapy for patients with progressive or symptomatic neuroendocrine tumor liver metastases. Long-term follow-up data on the safety of Yttrium-90 radioembolization before and after PRRT remain limited. Therefore, a more conservative approach may be to preferentially employ transarterial embolization (TAE) or transarterial chemoembolization (TACE) for patients' somatostatin receptor-avid disease who may be future candidates for PRRT. Notable exceptions where radioembolization may be a preferred treatment strategy may be patients with history of biliary tract instrumentation, asymmetric unilobar disease distribution, and rapidly progressive diffuse liver involvement. Selection of local treatment modality, sequencing, and combination of LDT with systemic therapy require further investigation.

Developments in interventional management of hepatic metastases from neuroendocrine tumours

Neuroendocrine tumours commonly metastasise to the liver, particularly those arising from the intestinal tract and pancreas. Whilst surgery offers the only approach with intent to cure, the vast majority of patients with neuroendocrine liver metastases are ineligible. Liver-directed interventional therapies seek to exploit the patho-anatomy of the blood supply of hepatic metastases to deliver therapy to liver deposits. This may involve percutaneous ablation, bland embolization, or the selective infusion of chemotherapeutics, targeted agents or radiolabelled embolic material. Retrospective case series evidence has characterised objective response rates, disease control rates, and longer-term outcomes associated with each approach. Recent advances in this field include ongoing comparative trials of different techniques, but more importantly, combinations of interventional liver-directed therapies and other systemic therapy in multimodal treatment concepts.

Transplantation for metastatic liver disease

The liver is a common site of metastases from many cancers, particularly those originating in the gastrointestinal tract. Liver transplantation is an uncommonly used but promising and at times controversial treatment option for neuroendocrine and colorectal liver metastases. Transplantation with meticulous patient selection has been associated with excellent long-term outcomes in individuals with neuroendocrine liver metastases, but questions remain regarding the role of transplantation in those who could also be eligible for hepatectomy, the role of neoadjuvant/adjuvant treatments in minimising recurrence, and the optimal timing of the procedure. A prospective pilot study of liver transplantation for unresectable colorectal liver metastases that reported a 5-year overall survival rate of 60% reinvigorated interest in this area following initially dismal outcomes. This has been followed by larger studies, and prospective trials are ongoing to quantify the potential benefits of liver transplantation over palliative chemotherapy. This review provides a critical summary of currently available knowledge on liver transplantation for neuroendocrine and colorectal liver metastases, and highlights avenues for further study to address gaps in the evidence base.

Gastro-Enteric-Pancreatic Neuroendocrine Tumor Treatment: 177Lu-DOTATATE

177Lu-DOTA-TATE therapy is a highly effective therapy in metastatic, well-differentiated, somatostatin receptor-positive GEP-neuroendocrine tumors (NETs) with mostly tolerable adverse effects. Guidelines generally refer to peptide receptor radionuclide therapy as a second-line therapy after SSA in gastroenteric and second- or third-line therapy in pancreatic NETs to improve survival rates and quality of life. Although we do not have sufficient data, 177Lu-DOTA-TATE therapy may also have a role in high-grade NET therapy, mostly in combination with other treatments such as chemotherapy.

Defining a New Classification System for the Surgical Management of Neuroendocrine Tumor Liver Metastases

Although rarely curative, hepatic cytoreduction of neuroendocrine tumor liver metastases (NETLM) is associated with improved symptom control and prolonged survival. Preoperative 68Ga DOTATATE and gadoxetic acid-enhanced liver MRI can improve characterization of hepatic disease extent to improve surgical clearance, and resection of the primary tumor is associated with improved survival regardless of whether the liver metastases are treated. As parenchymal-sparing surgical techniques and the lowering of the debulking threshold have expanded the numbers of eligible NETLM patients for hepatic cytoreduction, we propose a new classification system to help guide surgical management. A multimodal approach that includes surgery, liver-directed therapies, and systemic therapies has improved outcomes and increased longevity for patients with well-differentiated metastatic NET.

A Clinical Guide to Peptide Receptor Radionuclide Therapy with 177Lu-DOTATATE in Neuroendocrine Tumor Patients

Peptide receptor radionuclide therapy (PRRT) with [¹⁷⁷Lu]Lu-[DOTA⁰,Tyr³]-octreotate (¹⁷⁷Lu-DOTATATE) has become an established second- or third-line treatment option for patients with somatostatin receptor (SSTR)-positive advanced well-differentiated gastroenteropancreatic (GEP) neuroendocrine tumors (NETs). Clinical evidence of the efficacy of PRRT in tumor control has been proven and lower risks of disease progression or death are seen combined with an improved quality of life. When appropriate patient selection is performed, PRRT is accompanied by limited risks for renal and hematological toxicities. Treatment of NET patients with PRRT requires dedicated clinical expertise due to the biological characteristics of PRRT and specific characteristics of NET patients. This review provides an overview for clinicians dealing with NET on the history, molecular characteristics, efficacy, toxicity and relevant clinical specifics of PRRT.

Optimisation of radioligand therapy in neuroendocrine tumours: Current and evolving evidence

Treatment of neuroendocrine tumours (NETs) with radioligand therapy (RLT) for example, ¹⁷⁷ Lu-DOTATATE is generally well-tolerated and prolongs time to progression in most patients. However, approximately 20% of patients are nonresponders. In addition, complete responses are rare (<5% of patients), and durable responses beyond 3-4 years are uncommon. This article will discuss factors which may improve the outcomes of PRRT by using biomarkers to identify patients at high risk to be nonresponders (imaging and liquid biomarkers) and will examine mechanisms to potentially improve/optimise current RLT treatment strategies. These include mechanisms to potentiate the effects of RLT, increase tumour absorbed dose, overcoming radio-resistance and upregulation of somatostatin receptors, although larger studies will be required to demonstrate which techniques are going to be most efficacious in clinical practice.

Case report - Selective internal radiation therapy (SIRT) in a patient with hyperinsulinemic hypoglycemia due to a metastatic insulinoma with late onset of endocrine activity

Insulinomas are the most common functioning pancreatic neuroendocrine tumors (NET), which can lead to hyperinsulinemic hypoglycemia. In advanced metastatic stages of the disease, the prognosis is poor. Patients with hormonally active insulinomas primarily present with features of neuroglycopenia. Transformation from a nonfunctional to a functional NET is rare. Here, we present a case of a 59-year-old male adult with a metastatic insulinoma and late onset of endocrine activity. Besides medical treatment with Diazoxide and small frequent feedings, continuous intravenous glucose application was eventually required to avoid hypoglycemia. Furthermore, we show that selective internal radiation therapy (SIRT) can be an effective therapeutic approach for symptom reduction in advanced metastatic disease.

Neuroendocrine Tumors and Peptide Receptor Radionuclide Therapy: When Is the Right Time?

Since its approval in 2018 by the US Food and Drug Administration, peptide receptor radionuclide therapy (PRRT) has become a mainstay in the treatment of neuroendocrine tumors. Lutetium-177-DOTATATE, the only approved agent, is indicated for the treatment of gastroenteropancreatic-neuroendocrine tumors. Although patient selection appears straightforward with somatostatin receptor-positron emission tomography, there is considerable complexity when deciding which patients to treat and when to start PRRT. Herein, we review the many factors that affect patient selection, focusing on the optimal patients to treat. Although significant effort has been expended to determine which patients benefit the most from PRRT, a validated predictive biomarker remains elusive. Although PRRT has been used for more than 2 decades in Europe and standards of care exist for safe treatment, there remain numerous questions regarding when PRRT should be used relative to other treatments. It is important to remember that multidisciplinary discussions are essential. Currently, there are a number of ongoing studies looking to assess the efficacy of PRRT compared with other treatment options and to optimize treatment through combination therapy, different dosing strategies, or use of different radionuclides and radioligands.

Role of Radioembolization in Metastatic Neuroendocrine Tumors

The liver is the most common site of metastasis for neuroendocrine tumors originating from the gastrointestinal tract. Neuroendocrine liver metastases (NELMs) portend a worsening clinical course, making local management important. Local treatment options include surgery, thermal ablation, and trans-catheter intra-arterial therapies, such as radioembolization. Radioembolization is generally preferred over other embolotherapies in patients with colonized biliary systems. Current best practice involves personalized treatment planning, optimizing tumor radiation absorbed dose and minimizing radiation to the normal hepatic parenchyma. As part of a multidisciplinary approach, radioembolization is a versatile embolotherapy offering neoadjuvant, palliative, and ablative treatment options for patients with NELMs.

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.

Clinical Management of Neuroendocrine Neoplasms in Clinical Practice: A Formal Consensus Exercise

Simple Summary

Well-structured international guidelines are currently available regarding the management of patients with neuroendocrine neoplasms (NENs). However, in relation to the multiplicity of treatments and the relative rarity and heterogeneity of NENs, there are many controversial issues in which clinical evidence is insufficient and for which expert opinion can be of help. A group of experts selected 14 relevant topics and formulated relative statements concerning controversial issues in several areas on diagnosis, prognosis, therapeutic strategies, and patient follow-up. Specific statements have also been formulated regarding patient management on radioligand therapy (RLT), as well as in the presence of co-morbidities or bone metastases. All the statements were drafted, discussed, modified, and then approved. The Nominal Group Technique (NGT) method was used to obtain consensus. The results of this paper can facilitate the clinical approach of patients with NENs in daily practice in areas where there is scarcity or absence of clinical evidence.

Abstract

Many treatment approaches are now available for neuroendocrine neoplasms (NENs). While several societies have issued guidelines for diagnosis and treatment of NENs, there are still areas of controversy for which there is limited guidance. Expert opinion can thus be of support where firm recommendations are lacking. A group of experts met to formulate 14 statements relative to diagnosis and treatment of NENs and presented herein. The nominal group and estimate-talk-estimate techniques were used. The statements covered a broad range of topics from tools for diagnosis to follow-up, evaluation of response, treatment efficacy, therapeutic sequence, and watchful waiting. Initial prognostic characterization should be based on clinical information as well as histopathological analysis and morphological and functional imaging. It is also crucial to optimize RLT for patients with a NEN starting from accurate characterization of the patient and disease. Follow-up should be patient/tumor tailored with a shared plan about timing and type of imaging procedures to use to avoid safety issues. It is also stressed that patient-reported outcomes should receive greater attention, and that a multidisciplinary approach should be mandatory. Due to the clinical heterogeneity and relative lack of definitive evidence for NENs, personalization of diagnostic–therapeutic work-up is crucial.

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.

Long-term outcomes following 90Y Radioembolization of neuroendocrine liver metastases: evaluation of the radiation-emitting SIR-spheres in non-resectable liver tumor (RESiN) registry

Background

The goal of this study was to evaluate efficacy and safety of 90Y radioembolization for neuroendocrine liver metastases (NELM) in a multicenter registry.

Methods

One hundred-seventy patients with NELM were enrolled in the registry (NCT 02685631). Prior treatments included hepatic resection (n = 23, 14%), arterial therapy (n = 62, 36%), octreotide (n = 119, 83%), cytotoxic chemotherapy (n = 58, 41%), biologic therapy (n = 49, 33%) and immunotherapy (n = 10, 6%). Seventy-seven (45%) patients had extrahepatic disease. Seventy-eight (48%), 61 (37%), and 25 (15%) patients were Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or ≥ 2. Tumor grade was known in 81 (48%) patients: 57 (70%) were well-, 12 (15%) moderate-, and 12 (15%) poorly-differentiated. Kaplan-Meier analysis and log rank tests were performed to compare overall and progression-free survival (OS/PFS) by tumor location and grade. Toxicities were reported using Common Terminology Criteria for Adverse Events v.5. Cox Proportional Hazards were calculated for pancreatic primary, performance status, extrahepatic disease at treatment, unilobar treatment, baseline ascites, and > 25% tumor burden.

Results

One, 2, and 3-year OS rates were 75, 62 and 46%, respectively. Median OS was 33 months [(95% CI: 25-not reached (NR)]. The longest median OS was in patients with pancreatic (42 months, 95% CI: 33-NR) and hindgut 41 months, 95% CI: 12-NR) primaries. The shortest OS was in foregut primaries (26 months; 95% CI: 23-NR; X² = 7, p = 0.1). Median OS of well-differentiated tumors was 36 months (95% CI: 10-NR), compared to 44 (95% CI: 7-NR) and 25 (95% CI: 3-NR) months for moderate and poorly differentiated tumors. Median progression-free survival (PFS) was 25 months with 1, 2, and 3-year PFS rates of 70, 54, and 35%, respectively. Thirteen patients (7.6%) developed grade 3 hepatic toxicity, most commonly new ascites (n = 8, 5%) at a median of 5.5 months. Performance status of ≥2 (HR 2.7, p = 0.01) and baseline ascites (HR 2.8, P = 0.049) predicted shorter OS.

Discussion

In a population with a high incidence of extrahepatic disease, 90Y was effective and safe in treatment of NELM, with median OS of 41 months for well differentiated tumors. Grade 3 or greater hepatic toxicity was developed in 7.6% of patients.

Trial registration

NCT 02685631.

Liver-Directed Therapy for Neuroendocrine Metastases: From Interventional Radiology to Nuclear Medicine Procedures

Neuroendocrine neoplasms (NENs) are rare and heterogeneous epithelial tumors most commonly arising from the gastroenteropancreatic (GEP) system. GEP-NENs account for approximately 60% of all NENs, and the small intestine and pancreas represent two most common sites of primary tumor development. Approximately 80% of metastatic patients have secondary liver lesions, and in approximately 50% of patients, the liver is the only metastatic site. The therapeutic strategy depends on the degree of hepatic metastatic invasion, ranging from liver surgery or percutaneous ablation to palliative treatments to reduce both tumor volume and secretion. In patients with grade 1 and 2 NENs, locoregional nonsurgical treatments of liver metastases mainly include percutaneous ablation and endovascular treatments, targeting few or multiple hepatic metastases, respectively. In the present work, we provide a narrative review of the current knowledge on liver-directed therapy for metastasis treatment, including both interventional radiology procedures and nuclear medicine options in NEN patients, taking into account the patient clinical context and both the strengths and limitations of each modality.

Peptide receptor radionuclide therapy with [177Lu]Lu-DOTA-TATE

This continuing education aims to present in a clear and easy-to-understand way, the biology of neuroendocrine tumors (NETs), the characteristics of somatostatin receptors, the selection of patients for radiolabelled peptide therapy (PRRT), the inclusion criteria to benefit from treatment with the minimum possible adverse effects, the administration protocol, follow-up and response evaluation. The functional imaging studies necessary to explore the biology of the tumor and to individualize the treatment are also carried out, and constitute the cornerstone for the development of teragnosis. Clinical trials are being developed to better define the position of PRRT within the broad therapeutic options, and among the future perspectives, there are several lines of research to improve the objective response rate and survival with PRRT, focused on the development of new agonists and somatostatin receptor antagonists, new radionuclides and radiosensitizing combination therapies. In conclusion, PRRT is a great therapeutic, well-tolerated and safe tool with generally mild and self-limited acute side effects, that must be sequenced at the best moment of the evolution of the disease of patients with NET. Candidate patients for PRRT should always be evaluated by a multidisciplinary clinical committee.

Progress in the Management of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) are a heterogeneous and orphan group of neoplasms that vary in their histology, clinical features, prognosis, and management. The treatment of PNETs is highly dependent on the stage at presentation, tumor grade and differentiation, presence of symptoms from hormonal overproduction or from local growth, tumor burden, and rate of progression. The US Food and Drug Administration has recently approved many novel treatments, which have altered decision making and positively impacted the care and prognosis of these patients. In this review, we focus on the significant progress made in the management of PNETs over the past decade, as well as the active areas of research. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Radioembolization in the Setting of Systemic Therapies

90 Yttrium (Y90) radioembolization has been shown to improve outcomes for primary and metastatic liver cancers, but there is limited understanding of the optimal timing and safety of combining systemic therapies with Y90 treatment. Both therapeutic effects and toxicities could be synergistic depending on the timing and dosing of different coadministration paradigms. In particular, patients with liver-only or liver-dominant metastatic disease progression are often on systemic therapy when referred to interventional radiology for consideration of Y90 treatment. Interventional radiologists are frequently asked to offer insight into whether or not to hold systemic therapy, and for how long, prior to and following transarterial therapy. This study reviews the current evidence regarding the timing and safety of systemic therapy with Y90 treatment for hepatocellular carcinoma, metastatic colorectal carcinoma, intrahepatic cholangiocarcinoma, metastatic neuroendocrine tumors, and other hepatic metastases. A particular focus is placed on the timing, dosing, and toxicities of combined therapy.

Combination Therapies with PRRT

Peptide receptor radionuclide therapy (PRRT) is a successful targeted radionuclide therapy in neuroendocrine tumors (NETs). However, complete responses remain elusive. Combined treatments anticipate synergistic effects and thus better responses by combining ionizing radiation with other anti-tumor treatments. Furthermore, multimodal therapies often have a balanced toxicity profile. To date, few studies have evaluated the effect of combination therapies with PRRT, some of them phase I/II trials. This review will focus on several clinically tested, tailored approaches to improving the effects of PRRT. The aim is to help clinicians in the treatment planning of NETs to choose the most effective and safe treatment for each patient in the sense of personalized medicine. Current promising combination partners of PRRT are somatostatin analogues (SSAs), chemotherapy, molecular targeted treatment, liver radioembolization, and dual radionuclide PRRT (Lutetium-177-PRRT combined with Yttrium-90-PRRT).

Incidence and risk factors for sustained hepatic function toxicity 6 months after radioembolization: analysis of the radiation-emitting sir-spheres in non-resectable liver tumor (RESIN) registry

Background

To quantify rates and risk factors for toxicity after hepatic radioembolization using resin yttrium-90 microspheres.

Methods

Radiation-Emitting SIR-Spheres in Non-resectable liver tumor (RESIN) registry enrollees were reviewed with 614 patients included. Mean patient age was 63.1±12.5 years. The majority of patients were male (n=375, 61%) and white (n=490, 80%). Common tumor types were hepatocellular (n=197, 32%), colorectal (n=187, 30%) and neuroendocrine (n=56, 9%). Hepatotoxicity was measured using the Common Terminology Criteria for Adverse Events (CTCAE v 5). Potential risk factors for hepatotoxicity were tested using the Kruskal-Wallis or Pearson Chi-squared tests, and multivariate linear regressions.

Results

At 6 months, 115 patients (18.7%) died (n=91, 14.8%), entered hospice (n=20, 3.3%) or sought treatment elsewhere (n=4, 4%). Seven (1.1%) deaths were from liver decompensation. Grade 3 toxicity rates were: bilirubin (n=85, 13.8%), albumin (n=28, 4.6%), ALT (n=26, 4.2%) and AST (n=37, 6.0%). For each of these liver function test components, baseline abnormal labs predicted Grade 3 toxicity at follow-up by Kruskal-Wallis test (P<0.001) and linear regression (all P<0.03). Other significant factors predicting toxicity at regression included elevated Body-Mass Index (albumin P=0.0056), whole liver treatment (bilirubin P=0.046), and lower tumor volume (ALT and INR, P<0.035 for both).

Conclusions

Baseline liver function abnormalities prior to radioembolization is the strongest predictor of post-treatment Grade 3 toxicity with rates as high as 13.8%. Toxicity rates for specific lab values are affected by large volume treatments especially with low tumor volumes.

Currently available treatment options for neuroendocrine liver metastases

Neuroendocrine neoplasms (NEN) are frequently characterized by a high propensity for metastasis to the liver, which appears to be a dominant site of distant-stage disease, affecting quality of life and overall survival. Liver surgery with the intention to cure is the treatment of choice for resectable neuroendocrine liver metastases (NELM), aiming to potentially prolong survival and ameliorate hormonal symptoms refractory to medical control. Surgical resection is indicated for patients with NELM from well-differentiated NEN, while its feasibility and complexity are largely dictated by the degree of liver involvement. As a result of advances in surgical techniques over the past decades, complex 1- and 2-stage, or repeat liver resections are performed safely and effectively by experienced surgeons. Furthermore, liver transplantation for the treatment of NELM should be anchored in a multimodal and multidisciplinary therapeutic strategy and restricted only to highly selected individual cases. A broad spectrum of interventional radiology treatments for NELM have recently been available, with expanding indications that are more applicable, as they are less limited by patient- and tumor-related parameters, being therefore important adjuncts or alternatives to surgery. Overall, liver-targeted treatment modalities may precede the administration of systemic molecular targeted agents and chemotherapy for patients with liver-dominant metastatic disease; these appear to be a crucial component of multimodal management of patients with NEN. In the present review, we discuss surgical and non-surgical liver-targeted treatment approaches for NELM, each complementing the other, with a view to assisting physicians in optimizing multimodal NEN patient care.

Advances in Molecular Imaging and Radionuclide Therapy of Neuroendocrine Tumors

Neuroendocrine neoplasms make up a heterogeneous group of tumors with inter-patient and intra-patient variabilities. Molecular imaging can help to identify and characterize neuroendocrine tumors (NETs). Furthermore, imaging and treatment with novel theranostics agents offers a new, tailored approach to managing NETs. Recent advances in the management of NETs aim to enhance the effectiveness of targeted treatment with either modifications of known substances or the development of new substances with better targeting features. There have been several attempts to increase the detectability of NET lesions via positron emission tomography (PET) imaging and improvements in pretreatment planning using dosimetry. Especially notable is PET imaging with the radionuclide Copper-64. Increasing interest is also being paid to theranostics of grade 3 and purely differentiated NETs, for example, via targeting of the C-X-C motif chemokine receptor 4 (CXCR4). The aim of this review is to summarize the most relevant recent studies, which present promising new agents in molecular imaging and therapy for NETs, novel combination therapies and new applications of existing molecular imaging modalities in nuclear medicine.

Clinicopathological Features of Gastroesophageal Neuroendocrine Neoplasms

PURPOSE OF REVIEW

Gastroesophageal neuroendocrine neoplasms (NENs) are a rare entity. Recent 2019 WHO classifications reflect our understanding of tumor biology, namely, that distinct molecular characteristics underline tumor behavior and prognosis. Here, we reviewed the evidence for linking molecular findings with the clinicopathological features and treatment of gastroesophageal NENs.

RECENT FINDINGS

Degree of differentiation and Ki-67 proliferation index are required for accurate classification of neuroendocrine tumors and carcinomas but not sufficient to distinguish between the two entities. Resection remains the mainstay treatment for early-stage gastroesophageal neuroendocrine tumors. Additional perioperative therapy may benefit mitotically active tumors. There is a role for somatostatin analogues, especially in the setting of metastatic and symptomatic disease. New radiolabeled somatostatin analogues, immunotherapy, and embolization offer multimodality treatments for distant metastases. We need to understand the specific underlying biology of the various subtypes of gastroesophageal NENs to provide tailored treatment.

The Role of Interventional Radiology for the Treatment of Hepatic Metastases from Neuroendocrine Tumor: An Updated Review

Interventional radiology plays an important role in the management of patients with neuroendocrine tumor liver metastasis (NELM). Transarterial embolization (TAE), transarterial chemoembolization (TACE), and selective internal radiation therapy (SIRT) are intra-arterial therapies available for these patients in order to improve symptoms and overall survival. These treatment options are proposed in patients with NELM not responding to systemic therapies and without extrahepatic progression. Currently, available data suggest that TAE should be preferred to TACE in patients with NELM from extrapancreatic origin because of similar efficacy and better patient tolerance. TACE is more effective in patients with pancreatic NELM and SIRT has shown promising results along with good tolerance. However, large randomized controlled trials are still lacking in this setting. Available literature mainly consists in small sample size and retrospective studies with important technical heterogeneity. The purpose of this review is to provide an updated overview of the currently reported endovascular interventional radiology procedures that are used for the treatment of NELM.

Additional holmium-166 radioembolisation after lutetium-177-dotatate in patients with neuroendocrine tumour liver metastases (HEPAR PLuS): a single-centre, single-arm, open-label, phase 2 study

BACKGROUND

In patients with metastatic neuroendocrine neoplasms, the liver is the most commonly affected organ and a crucial factor for prognosis and survival. Peptide receptor radionuclide therapy can prolong progression-free survival in these patients. Additional treatment of liver disease might further improve outcomes. We aimed to investigate the safety and efficacy of additional holmium-166 (¹⁶⁶Ho) radioembolisation after peptide receptor radionuclide therapy in patients with metastatic liver neuroendocrine neoplasms.

METHODS

The Holmium Embolization Particles for Arterial Radiotherapy Plus ¹⁷⁷Lu-Dotatate in Salvage Neuroendocrine Tumour Patients (HEPAR PLuS) study was a single-centre, phase 2 study done at the University Medical Center Utrecht (Utrecht, Netherlands). Patients, aged at least 18 years, with histologically proven grade 1 or 2 neuroendocrine neoplasms of all origins, an Eastern Cooperative Oncology Group performance status of 0-2, and three or more measurable liver metastases according to Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1 criteria received ¹⁶⁶Ho-radioembolisation within 20 weeks after four cycles of peptide receptor radionuclide therapy (lutetium-177-dotatate [¹⁷⁷Lu-dotatate]). The primary endpoint was objective liver tumour response in the treated liver volume, defined as complete response (disappearance of all lesions) or partial response (≥30% decrease in the sum of the longest diameters of the target lesions, compared with baseline measurements), according to RECIST 1.1, analysed per protocol at 3 months. Safety was assessed in all patients who received treatment. This study is registered with ClinicalTrials.gov, NCT02067988. Recruitment is completed and long-term follow-up is ongoing.

FINDINGS

From Oct 15, 2014, to Sept 12, 2018, 34 patients were assessed for eligibility. 31 patients received treatment and 30 (97%) patients were available for primary endpoint assessment and completed 6 months of follow-up. Three (9%) patients were excluded at screening and one (3%) patient was treated and died before the primary endpoint and was replaced. According to the per-protocol analysis 13 (43%; 95% CI 26-63) of 30 patients achieved an objective response in the treated volume. The most frequently reported Common Terminology Criteria for Adverse Events (CTCAE) grade 3-4 clinical and laboratory toxicities within 6 months included abdominal pain (three [10%] of 31 patients), increased γ-glutamyl transpeptidase (16 [54%]), and lymphocytopenia (seven [23%]). One (3%) fatal treatment-related serious adverse event occurred (radioembolisation-induced liver disease). Two (6%) patients had serious adverse events deemed to be unrelated to treatment (gastric ulcer and perforated cholecystitis).

INTERPRETATION

¹⁶⁶Ho-radioembolisation, as an adjunct to peptide receptor radionuclide therapy in patients with neuroendocrine neoplasm liver metastases, is safe and efficacious. Radioembolisation can be considered in patients with bulky liver disease, including after peptide receptor radionuclide therapy. A future randomised, controlled study should investigate the added benefit of this treatment on progression-free survival.

FUNDING

None.

CAN MICROWAVE ABLATION BE AN ALTERNATIVE TO RESECTION FOR THE TREATMENT OF NEUROENDOCRINE LIVER METASTASES?

Objective: Surgical resection of neuroendocrine tumor liver metastases has been proven to improve survival, but the benefit of microwave ablation as an alternative or adjunct to surgery has yet to be assessed. Our hypothesis is that ablation is equal to surgery in terms of local recurrence and survival. Methods: We conducted a retrospective analysis including all patients treated with microwave ablation and/or surgical resection for neuroendocrine liver metastases in our institution between 2008 and 2017. Results: A total of 47 patients and 68 treatments were analyzed, including 34 liver resections, 20 ablations, and 14 combined procedures. A total of 130 individual metastases were treated with ablation, representing a median of 4 per session (range 1-30). While no major complications occurred after ablation, we observed 11 minor and 3 major complications after open surgical resection (P = .0135). Length of stay was significantly shorter after ablation (P = .0008). The majority of patients (33/47, 70.2%) underwent curative procedures, 14 patients underwent (29.8%) debulking procedures. There was no difference in local recurrence rate between tumors treated with ablation or resection. Liver-only disease progression was detected in 29% of the patients and overall progression was detected in 66% of the patients. The mean survival was not significantly different between patients treated with ablation only versus resection with or without ablation (P = .1570). Overall survival was mean 75.3 months (6 to 374 months). Conclusion: Depending on the extent of the liver metastases, microwave ablation might be a safe alternative or addition to resection for neuroendocrine tumor liver metastases with low morbidity and high local efficiency. Abbreviations: CT = computed tomography; MWA = microwave ablation; NET = neuroendocrine tumor; PET = positron emission tomography; RFA = radiofrequency ablation; RFS = recurrence-free survival; SMWA = stereotactic microwave ablation.