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

Transarterial radioembolization in neuroendocrine liver metastases 25 years later: A systematic review

Transarterial Radioembolization (TARE) currently lacks a defined role in treating neuroendocrine liver metastases (NELM). This systematic review aims to clarify TARE's role based on its prognostic impact. A search identified 138 studies onPubMed/MEDLINE over the past 25 years, focusing on TARE for NELM patients. Of these, 46 studies met eligibility criteria, and 11 were selected for their similar settings, populations, and outcomes. These were grouped into three clusters based on survival outcomes: overall survival (OS), hepatic progression-free survival (HPFS), and imaging response (IR) per RECIST 1.1 criteria. Statistical analyses showed a median OS of 33 months for 809 patients, a median HPFS of 24 months for 414 patients, and an IR of 28.6 % complete or partial response, 57.8 % stable disease, and 13.6 % disease progression in 581 patients. This evidence supports TARE as a viable treatment option, but further studies are needed to optimize its use and dosimetric procedures.

Treatment of Pancreatic Neuroendocrine Tumors: Beyond Traditional Surgery and Targeted Therapy

Pancreatic neuroendocrine tumors (PNETs) are a rare subset of pancreatic neoplasms with diverse biological behavior and clinical presentations. Traditional treatment approaches, such as surgery and targeted therapies, have significantly improved outcomes. However, advancements in molecular biology, immunotherapy, and minimally invasive techniques have ushered in a new era of treatment possibilities. This manuscript explores the emerging modalities in PNET management, emphasizing the need for a multidisciplinary approach tailored to individual patient profiles.

PRRT plus holmium-166-SIRT (HEPAR PLuS) versus PRRT-only in patients with metastatic neuroendocrine tumors: A propensity-score matched analysis

Patients with bulky neuroendocrine liver metastases (NELM) undergoing PRRT with [177Lu]Lu-DOTATATE have a worse survival than patients with limited liver metastases. Previously, the safety and efficacy of additional selective internal radiotherapy (SIRT), using holmium-166 (166Ho)-microspheres, directly following PRRT in patients with NELM were confirmed in the prospective HEPAR PLuS study. The aim of the current study was to provide insight into the efficacy and survival benefit of PRRT + 166Ho-SIRT over PRRT-only by means of a propensity score matched historical cohort. A multicenter retrospective data collection was performed to match patients treated with PRRT-only to the prospectively collected HEPAR PLuS study patients. Demographic, clinical, laboratory, and imaging data were collected. The primary endpoint was the proportion of patients with progression-free survival (PFS) at 2 years after the start of PRRT. Secondary endpoints included the proportion of patients with 2-year hepatic PFS (hPFS), general PFS and hPFS, objective response rates (ORR), and overall survival (OS). Twenty-four patients were 1:1 matched and included in the analysis. All key matching criteria were balanced between cohorts if feasible. The proportion of patients with PFS and hPFS at 2 years was 68% and 82% after PRRT + 166Ho-SIRT versus 55% and 50% after PRRT only. Time to median PFS was comparable (31 vs. 30 months). An initial delay in hepatic progression or death of any cause was observed in PRRT + 166Ho-SIRT mNET patients (75% probability of PFS at 27 vs. 22 months), most notably in intestinal tumors (75% probability of PFS at 26 vs. 15 months). Best ORR was 71% after PRRT + 166Ho-SIRT versus 25% after PRRT only. This study showed that 166Ho-SIRT after PRRT (vs. PRRT-only) had a positive effect on the liver disease progression in patients with NELM, increasing the 2-year hPFS rate and tumor response and delaying hepatic progression or death. However, this effect did not translate into improving general PFS and OS.

Y-90 Selective Internal Radiation Therapy for Inoperable, Chemotherapy-Resistant Liver Metastases: A Meta-analysis

RATIONALE AND OBJECTIVES

Yttrium-90 (Y-90) radioembolization has emerged as an effective therapeutic modality for patients with liver metastases, despite the absence of Level I evidence. The objective of this study is to evaluate the efficacy of this treatment approach through a meta-analysis of the available literature.

METHODS

A comprehensive review protocol was implemented to screen all relevant reports in the literature. Strict inclusion criteria were applied to ensure consistency among the following selected studies: individual and complete data on Y-90 treatment for liver metastases, even if the studies included various tumor types. The selected studies were rigorously assessed according to the Reporting Standards of Radioembolization, based on 28 study criteria. Response data were extracted and analyzed using both fixed-effect and random-effect meta-analysis models.

RESULTS

A total of 28 studies, involving 1662 patients, were included. Begg's test showed no significant evidence of publication bias. The random-effects weighted average overall response rate (complete response [CR] and partial response [PR]) was 34% (range: 26%-44%, I²=86%). The disease control rate (CR, PR, and stable disease [SD]) was 64% (range: 53%-75%, I²=91%). The progressive disease rate was 24% (range: 16%-33%, I²=87%), while the rate of adverse events was 57% (range: 16%-93%, I²=98%). The rate of grade 3-5 adverse events was 20% (range: 7%-36%, I²=9%).

CONCLUSION

This meta-analysis confirms that Yttrium-90 radioembolization is an effective treatment option for patients with liver metastases, demonstrating a high disease control rate with a relatively low incidence of severe adverse reactions.

Exploring Carcinoid Syndrome in Neuroendocrine Tumors: Insights from a Multidisciplinary Narrative Review

Carcinoid syndrome (CS) is a rare condition associated with neuroendocrine tumors (NETs), particularly those originating in the gastrointestinal tract, which secrete bioactive substances like serotonin. The management of CS requires a multidisciplinary approach due to its complex clinical manifestations, including flushing, diarrhea, bronchospasm, and carcinoid heart disease. Optimal care involves collaboration between several professional figures like oncologists, endocrinologists, gastroenterologists, surgeons, and dietitians. Currently, a wide range of treatments are available, focused on both symptom control and tumor burden reduction. Somatostatin analogs (SSAs) are the first-line therapy for symptom relief. Still, in patients with progressive disease or refractory CS, other options include targeted therapies, peptide receptor radionuclide therapy (PRRT), liver-directed therapies, and surgical resection, when feasible. Furthermore, management of complications related to prolonged serotonin release and malnutrition as a result of exocrine pancreatic insufficiency, post-surgical conditions, vitamin deficit, and chronic diarrhea often requires early detection to mitigate symptoms and improve the quality of life in these patients. The complexity of CS necessitates individualized care and continuous coordination among specialists to optimize outcomes and enhance patient well-being.

Outcomes Analysis of Yttrium-90 Radioembolization for Tumors Other Than Metastatic Colorectal Cancer from the Radiation-Emitting SIR-Spheres in Nonresectable (RESiN) Registry

PURPOSE

To characterize the response and survival outcomes of yttrium-90 (90Y) transarterial radioembolization (TARE) for unresectable, liver-dominant metastases from primary neoplasms other than colorectal carcinoma.

MATERIALS AND METHODS

This study included 1,474 patients enrolled in the Radiation-Emitting Society of Interventional Radiology (SIR)-Spheres in Nonresectable Liver Tumor registry who received resin 90Y-TARE as part of their oncologic management for unresectable primary or secondary liver tumors (NCT02685631). Of these patients, 33% (481/1,474) were treated for liver metastases of noncolorectal origin (m-non-CRC) compared with 34% (497/1,474) treated for metastatic colorectal cancer (mCRC) and 34% (496/1,474) treated for hepatocellular carcinoma. Treatment response and cancer survival probabilities were computed and compared for each primary cancer type. The Kaplan-Meier method and log-rank test were used to compare survival outcomes.

RESULTS

Radiological responses were observed in 12 unique cancer types, mostly heavily pretreated malignancies refractory to multiple lines of systemic therapies. The overall use of resin 90Y-TARE in m-non-CRC resulted in better treatment outcomes in terms of duration of response, progression-free survival, time to progression, and overall survival (P = .04, P = .02, P = .01, and P = .04, respectively). Analyses of cancer cell types revealed that metastatic neuroendocrine tumor, sarcoma, and ovarian, renal, prostate, and breast cancers were associated with superior treatment outcomes, whereas worse treatment outcomes were observed in metastatic lung, gastric, pancreatic, and esophageal cancers.

CONCLUSIONS

Real-world data demonstrate the use of resin 90Y-TARE in m-non-CRC refractory to standard chemotherapy. For some cell types, this expanded use achieved superior treatment outcomes relative to the reference standard of mCRC, suggesting the need for inquiry into broadened indications for 90Y-TARE.

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.

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.

A Side-Effect-Free Interventional Therapy for Precisely Eliminating Unresectable Cancer Pain

Of patients bearing unresectable tumors at advanced stages, most undergo serious pain. For unresectable tumors adjacent to vital organs or nerves, eliminating local cancer pain without adverse effects remains a formidable challenge. Interventional ablative therapies (IATs), such as radio frequency ablation (RFA), microwave ablation, and irreversible electroporation, have been clinically adopted to treat various carcinomas. In this study, we established another palliative interventional therapy to eliminate local cancer pain, instead of relieving nociception temporarily. Here, we developed another interventional ablative therapy (termed nanoparticle-mediated microknife ablation) to locoregionally eliminate cancer pain and tumors. The IAT system was composed of self-assembled nanodrugs, infusion catheters, puncture needles, injection pump, and an empirical tumor ablation formula. Notably, the ablation formula established in the IAT system enables us to predict the essential nanoparticle (NP) numbers used for completely destroying tumors. In a mouse model of cancer pain, tumor-targeted nanodrugs made of Paclitaxel and Hematoporphyrin, which have an extremely high drug-loading efficiency (more than 60%), were infused into tumors through injection pumps under imaging guidance. In conclusion, when compared to classic chemotherapeutic agents, IAT showed significantly higher effectiveness in cancer pain removal. It also presented no damage to the nervous, sensory, and motor capabilities of the treated mice. All of these merits resulted from NPs' long-lasting retention, targeted ablation, and confined diffusion in tumor stroma. Therefore, this safe treatment modality has great potential to eradicate local cancer pain in the clinic.

Radioembolisation of liver metastases

This review aims to present contemporary data for SIRT in the treatment of secondary hepatic malignancies including colorectal, neuroendocrine, breast and uveal melanoma.

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.

Effective Treatment of SSTR2-Positive Small Cell Lung Cancer Using 211At-Containing Targeted α-Particle Therapy Agent Which Promotes Endogenous Antitumor Immune Response

Small cell lung cancer (SCLC) is a neuroendocrine tumor with a high degree of malignancy. Due to limited treatment options, patients with SCLC have a poor prognosis. We have found, however, that intravenously administered octreotide (Oct) armed with astatine-211 ([211At]SAB-Oct) is effective against a somatostatin receptor 2 (SSTR2)-positive SCLC tumor in SCLC tumor-bearing BALB/c nude mice. In biodistribution analysis, [211At]SAB-Oct achieved the highest concentration in the SCLC tumors up to 3 h after injection as time proceeded. A single intravenous injection of [211At]SAB-Oct (370 kBq) was sufficient to suppress SSTR2-positive SCLC tumor growth in treated mice by inducing DNA double-strand breaks. Additionally, a multitreatment course (370 kBq followed by twice doses of 370 kBq for a total of 1110 kBq) inhibited the growth of the tumor compared to the untreated control group without significant off-target toxicity. Surprisingly, we found that [211At]SAB-Oct could up-regulate the expressions of calreticulin and major histocompatibility complex I (MHC-I) on the tumor cell membrane surface, suggesting that α-particle internal irradiation may activate an endogenous antitumor immune response through the regulation of immune cells in the tumor microenvironment, which could synergically enhance the efficacy of immunotherapy. We conclude that [211At]SAB-Oct is a potential new therapeutic option for SSTR2-positive SCLC.

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.

A Comparison of the Outcomes of Transarterial Chemoembolization and Transarterial Radioembolization in the Management of Neuroendocrine Liver Metastases in Adults: A Systematic Review

The purpose of this article is to review the existing English scientific literature and determine the superior modality between transarterial chemoembolization (TACE) and radioembolization (TARE) in the treatment of neuroendocrine liver metastases (NELMs). To that end, we followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to search PubMed, the Cochrane Library, and Google Scholar. We identified 14 observational studies and no randomized controlled trials (RCTs) investigating the use of TACE or TARE to treat NELM. We used the Newcastle-Ottawa Scale to assess the risk of bias in these studies. We concluded that TACE and TARE appeared to have similar outcomes when comparing overall survival, progression-free survival, radiological response, symptomatic response, and the incidence of severe adverse events. Further large-scale RCTs are needed to identify the superior modality conclusively. We also identified several unique prognostic factors for overall survival, such as the neutrophil-lymphocyte ratio, volumetric multiparametric magnetic resonance imaging, serum albumin, alkaline phosphatase, and pancreastatin.

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.

The Evolving Role of Radioembolization in the Treatment of Neuroendocrine Liver Metastases

At diagnosis, 21-50% of neuroendocrine tumors already have distant metastases, of which the liver is most commonly affected. Unfortunately, the presence of neuroendocrine liver metastases (NELM) is the most incriminating factor for survival. At NELM diagnosis, 60-70% of patients suffer from bilobar multifocal disease, making them ineligible for surgical resection. With limited systemic options, a clinical need for liver-directed treatments exists. Trans-arterial (bland) embolization, chemoembolization and radioembolization have been increasingly used in the treatment of NELM. In recent years, radioembolization (also known as selective internal radiation therapy) has gained attention due to promising tumor reductive results, limited toxicities and increasing scientific evidence. This review provides basic insights into radioembolization as a technique, a summary of available literature on radioembolization in NELM, and discusses caveats, challenges and new insights when considering radioembolization in NELM.