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.

Chemoembolization Beyond Hepatocellular Carcinoma: What Tumors Can We Treat and When?

Liver metastases are the most common malignancy found in the liver and are 20 to 40 times more common than primary hepatic tumors, including hepatocellular carcinoma. Patients with liver metastases often present with advanced disease and are not eligible for curative-intent surgery or ablative techniques. The unique hepatic arterial blood supply of liver metastases allows interventional radiologists to target these tumors with transarterial therapies. Transarterial chemoembolization (TACE) has been studied in the treatment of liver metastases originating from a variety of primary malignancies and has demonstrated benefits in terms of hepatic progression-free survival, overall survival, and symptomatic relief, among other benefits. Depending on the primary tumor from which they originate, liver metastases may have different indications for TACE, may utilize different TACE regimens and techniques, and may result in different post-procedural outcomes. This review offers an overview of TACE techniques and specific considerations in the treatment of liver metastases, provides an in-depth review of TACE in the treatment of liver metastases originating from colorectal cancer, neuroendocrine tumor, and uveal melanoma, which represent some of the many tumors beyond hepatocellular carcinoma that can be treated by TACE, and summarizes data regarding when one should consider TACE in their treatment algorithms.

Integrated Capecitabine-Temozolomide with Radioembolization for Liver-Dominant G2 NETs: Long-Term Outcomes of a Single-Institution Retrospective Study

PURPOSE

Capecitabine-Temozolomide (CapTem) is an oral chemotherapy regimen for NETs. Both drugs are radiosensitizers. Integrating CapTem and Y90 transarterial radioembolization (TARE) in patients with grade 2 neuroendocrine tumor (NET) liver metastases achieved an encouraging objective response rate (ORR) and progression-free survival (PFS) in a feasibility study. This study expands that report to a larger cohort with longer follow-up.

METHODS

Therapy consisted of monthly cycles of capecitabine 600 mg/m2 twice daily for 14 days and temozolomide 150-200 mg/m2 on day 10-14. Simulation angiography was performed during the initial cycle. The dominant lobe was treated with 90Y-resin microspheres using BSA dosimetry on day 7 of the second cycle of CapTem. Patients with bilobar disease had the other lobe treated on day 7 of the third or fourth cycle. CapTem was continued until progression or intolerance. Clinical and laboratory assessment was done monthly and imaging every 3 months.

RESULTS

35/37 patients completed the prescribed regimen. Primary sites of disease were pancreas (16), lung (10), gut (7) and unknown (4). Mean duration of CapTem was 12 months (range, 4-32 months). ORR in the liver was 72% with a disease control rate of 100%. Median PFS was 36 months (95% CI, 25-45 months). Median overall survival was 41 months (95% CI, 24-87 months) from initiation of CapTemY90 therapy and 130 months (95% CI, 56-172 months) from initial diagnosis.

CONCLUSION

Chemoradiation with CapTem and TARE provided durable control of G2 NET liver metastases for substantially longer than expectations for embolotherapy or chemotherapy alone.

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.

Prolonged progression-free survival achieved by octreotide LAR plus transarterial embolization in low-to-intermediate grade neuroendocrine tumor liver metastases with high hepatic tumor burden

Objective

To evaluate the efficacy and outcome of transarterial embolization (TAE) plus octreotide long‐acting repeatable (LAR) on patients with low‐to‐intermediate neuroendocrine tumor liver metastases (NETLM).

Methods

One hundred and sixteen patients with G1/G2 NETLM treated with TAE plus octreotide LAR at the First Affiliated Hospital, Sun Yat‐sen University between January 12, 2016 and September 24, 2020 were reviewed. Radiological response was evaluated according to response evaluation criterion in solid tumor version 1.1. Overall progression‐free survival (PFS) was assessed. Intrahepatic and extrahepatic PFS were evaluated in the whole cohort and in patients with the extrahepatic disease (EHD), respectively. Factors affecting treatment response and overall PFS were analyzed using the logistic regression model and Cox proportional hazard model. Adverse events were recorded and evaluated according to Common Terminology Criteria for Adverse Events 5.0.

Results

The median overall PFS of the whole cohort was 13.6 months. For the patients with EHD, the median intrahepatic PFS and extrahepatic PFS were 13.6 and 26.1 months, respectively. The median overall PFS of patients with hepatic tumor burden (HTB) <10%, 10%–25%, 25%–50%, and >50% were 25.2, 13.6, 11.2, and 12.3 months, respectively. Ki67 >10%, HTB >50%, and bone metastasis were independently associated with overall PFS. The objective response rate was 78.4%. In patients with HTB 25%–50% and >50%, responders (complete response or partial response) had significant prolonged PFS compared with nonresponders (stable disease or progression disease). Ki67 >10%, bone metastasis, and clear tumor margin were independently associated with response to TAE. The most frequent adverse events that occurred after TAE were postembolization syndrome, and no treatment‐associated death occurred during the perioperative period.

Conclusion

Transarterial embolization plus octreotide LAR can significantly prolong the PFS of neuroendocrine tumor liver metastases, especially with high HTB over 50%. Selected patients with HTB >25% (ki67 ≤10%, absence of bone metastasis, clear tumor margin) could derive prognostic advantage from the combined treatment.

Liver Embolisation for Patients with Neuroendocrine Neoplasms: Systematic Review

BACKGROUND

Liver embolisation is one of the treatment options available for patients diagnosed with neuro-endocrine neoplasms (NEN). It is still uncertain whether the benefits of the various types of embolisation treatments truly outweigh the complications in NENs. This systematic review assesses the available data relating to liver embolisation in patients with NENs.

METHODS

Eligible studies (identified using MEDLINE-PubMed) were those reporting data on NEN patients who had undergone any type of liver embolisation. The primary end points were best radiological response and symptomatic response; secondary end-points included progression-free survival (PFS), overall survival (OS) and toxicity.

RESULTS

Of 598 studies screened, 101 were eligible: 16 were prospective (15.8%). The eligible studies included a total of 5,545 NEN patients, with a median of 39 patients per study (range 5-214). Pooled rate of partial response was 36.6% (38.9% achieved stable disease) and 55.2% of patients had a symptomatic response to therapy when pooled data were analysed. The median PFS and OS were 18.4 months (95% CI 15.5-21.2) and 40.7 months (95% CI 35.2-46.2) respectively. The most common toxicities were found to be abdominal pain (48.8%) and nausea (48.1%). Outcome did not significantly vary depending on the type of embolisation performed.

CONCLUSION

Liver embolisation provides adequate symptom relief for patients with carcinoid syndrome and is also able to reach partial response in a significant proportion of patients and a reasonable PFS. Quality of studies was limited, highlighting the need of further prospective studies to confirm the most suitable form of liver embolisation in NENs.

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.

The emerging role of targeted therapies for advanced well-differentiated gastroenteropancreatic neuroendocrine tumors

INTRODUCTION

Gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are unique and complex neoplasms, exhibiting a wide spectrum of diverse clinical behaviors. The contemporary management of well-differentiated GEP-NETs is marked by the availability of a wide range of targeted therapies. Areas Covered: For patients with localized or oligometastatic disease, surgical resection remains the preferred approach and is associated with excellent long-term outcomes. For patients with unresectable but isolated liver metastases, multiple liver-directed therapies, including hepatic arterial based therapies and ablative techniques, exist. For patients with metastatic and progressive disease, a number of systemic therapies exist: molecular targeted agents, peptide receptor radionuclide therapy (PRRT), and systemic chemotherapy. Furthermore, somatostatin analogs (SSA) are an important component of therapy, both effectively controlling symptoms of hormonal overproduction and contributing to slowing tumor progression. Expert Opinion: In the near future, advances in our understanding of tumor biology, genetics, immunology, nanotechnology, and radiation pharmacology should only continue to expand the availability of targeted therapies, improving the outcomes of patients with GEP-NETs. We herein review the management of advanced well-differentiated GEP-NETS with a particular emphasis on the role of targeted therapies.

Surgery Provides Long-Term Survival in Patients with Metastatic Neuroendocrine Tumors Undergoing Resection for Non-Hormonal Symptoms

INTRODUCTION

Patients with metastatic neuroendocrine tumor (NET) often have an indolent disease course yet the outcomes for patients with metastatic NET undergoing surgery for non-hormonal (NH) symptoms of GI obstruction, bleeding, or pain is not known.

METHODS

We identified patients with metastatic gastroenteropancreatic NET who underwent resection from 2000 to 2016 at 8 academic institutions who participated in the US Neuroendocrine Tumor Study Group.

RESULTS

Of 581 patients with metastatic NET to liver (61.3%), lymph nodes (24.1%), lung (2.1%), and bone (2.5%), 332 (57.1%) presented with NH symptoms of pain (n = 223, 67.4%), GI bleeding (n = 54, 16.3%), GI obstruction (n = 49, 14.8%), and biliary obstruction (n = 22, 6.7%). Most patients were undergoing their first operation (85.4%) within 4 weeks of diagnosis. The median overall survival was 110.4 months, and operative intent predicted survival (p < 0.001) with 66.3% undergoing curative resection. Removal of all metastatic disease was associated with the longest median survival (112.5 months) compared to debulking (89.2 months), or palliative resection (50.0 months; p < 0.001). The 1-, 3-, and 12-month mortality was 3.0%, 4.5%, and 9.0%, respectively. Factors associated with 1-year mortality included palliative operations (OR 6.54, p = 0.006), foregut NET (5.62, p = 0.042), major complication (4.91, p = 0.001), and high tumor grade (11.2, p < 0.001). The conditional survival for patients who lived past 1 year was 119 months.

CONCLUSIONS

Patients with metastatic NET and NH symptoms that necessitate surgery have long-term survival, and goals of care should focus on both oncologic and quality of life impact. Surgical intervention remains a critical component of multidisciplinary care of symptomatic patients.

Prognostic Impact of Serum Pancreastatin Following Chemoembolization for Neuroendocrine Tumors

PURPOSE

The objective of this study was to investigate the prognostic impact of the biomarker serum pancreastatin in patients with metastatic neuroendocrine tumors (NETs) treated with transarterial chemoembolization (TACE).

METHODS

Patients with metastatic NET treated with TACE at a single institution from 2000 to 2013 were analyzed. Patient demographics, response to therapy, and long-term survival were compared with baseline pancreastatin level and changes in pancreastatin levels after TACE.

RESULTS

A total of 188 patients underwent TACE during the study period. An initial pancreastatin level greater than 5000 pg/mL correlated with worse overall survival (OS) from time of first TACE (median OS, 58.5 vs. 22.1 months, p < 0.001). A decrease in pancreastatin level by 50% or more after TACE treatment correlated with improved OS (median OS 53.8 vs. 29.9 months, p = 0.032). Patients with carcinoid syndrome were more likely to have a subsequent increase in pancreastatin after initial drop post-TACE (78.1 vs. 55.2%, p = 0.002). Patients with an increase in pancreastatin levels after initial drop post-TACE were more likely to have liver progression on imaging (70.7 vs. 40.7%, p = 0.005) and more likely to need repeat TACE (21.1 vs. 6.7%, p = 0.009).

CONCLUSIONS

For patients with liver metastases from NET treated with TACE, pancreastatin measurement may be a useful prognostic indicator. Extreme high levels before TACE can predict poor outcomes, whereas significant drops in pancreastatin after TACE correlate with improved survival. An increase in levels after initial decrease may predict progressive liver disease requiring repeat TACE. As such, pancreastatin levels should be measured throughout the TACE treatment period.

Safety and Feasibility of Integrating Yttrium-90 Radioembolization With Capecitabine-Temozolomide for Grade 2 Liver-Dominant Metastatic Neuroendocrine Tumors

OBJECTIVES

An integrated protocol combining capecitibine-temozolomide with yttrium-90 radioembolization (CapTemY90) for liver-dominant grade 2 neuroendocrine tumors (NETs) was designed in the hope of achieving synergistic improvement in liver disease control with no more than additive toxicities. This report describes the feasibility and safety of this regimen.

METHODS

Twenty-one patients with unresectable grade 2 NET liver-dominant metastases without contraindications to radioembolization or to CapTem initiated therapy with capecitabine 600 mg/m twice daily for 14 days and temozolomide 150 to 200 mg/m in 2 divided doses on days 10 to 14, with 14 days between cycles. During the first cycle, simulation angiography was performed. The dominant lobe was radioembolized on day 7 of the second cycle. In patients with bilobar disease, the other lobe was treated on day 7 of the third or fourth cycle.

RESULTS

Nineteen of 21 patients completed the protocol. Adverse events were as expected. Objective response rate was 74% in the liver and 55% for extrahepatic tumor. Median progression-free survival was not reached. Progression-free survival at 3 years was 67%, with 74% progression-free in the liver.

CONCLUSIONS

CapTemY90 is feasible and safe for grade 2 NETs. Toxicities were additive. Oncologic outcomes suggest synergy.

Neutrophil Lymphocyte Ratio and Transarterial Chemoembolization in Neuroendocrine Tumor Metastases

BACKGROUND

The neutrophil-to-lymphocyte ratio (NLR) has been shown to be predictive of outcomes in various cancers, including neuroendocrine tumors (NETs), and cancer-related treatments, including transarterial chemoembolization (TACE). We hypothesized that NLR could be predictive of response to TACE in patients with metastatic NET.

METHODS

We reviewed 262 patients who underwent TACE for metastatic NET at a single tertiary medical center from 2000 to 2016. NLR was calculated from blood work drawn 1 d before TACE, as well as 1 d, 1 wk, and 6 mo after treatment.

RESULTS

The median post-TACE overall survival (OS) of the entire cohort was 30.1 mo. Median OS of patients with a pre-TACE NLR ≤ 4 was 33.3 mo versus 21.1 mo for patients with a pre-TACE NLR >4 (P = 0.005). At 6 mo, the median OS for patients with post-TACE NLR > pre-TACE NLR was 21.4 mo versus 25.8 mo for patients with post-TACE NLR ≤ pre-TACE NLR (P = 0.007). On multivariate analysis, both pre-TACE NLR and 6-mo post-TACE NLR were independent predictors of survival. NLR values from 1-d and 1-wk post-TACE did not correlate with outcome.

CONCLUSIONS

An elevated NLR pre-TACE and an NLR that has not returned to its pre-TACE value several months after TACE correlate with outcomes in patients with NET and liver metastases. This value can easily be calculated from laboratory results routinely obtained as part of preprocedural and postprocedural care, potential treatment strategies.

Liver transarterial embolizations in metastatic neuroendocrine tumors

The management of patients with well-differentiated neuroendocrine tumors (NET) and non-resectable liver metastases is challenging. Liver-directed transarterial embolization (TAE), transarterial chemo-embolization (TACE) and selective internal radiation therapy (SIRT) have a place of choice among other treatment modalities. However, their utilization relies on a low level of proof, due to the lack of prospective data, the absence of comparative studies and considerable heterogeneity between local practices. TAE and TACE generally achieve average symptomatic, biological and radiological responses of 75%, 56% and 50%, with progression-free survival of 12-18 months, with acceptable tolerance. Although not clearly demonstrated, TACE may be more effective than TAE in pancreatic NET, but not in small-intestine NET. SIRT has been developed more recently and may achieve similar results, with improved tolerance, but decreased cost-effectiveness, although no prospective comparison has been published to date. There is currently no strong argument to choose between TAE, TACE and SIRT, and they have not been compared to other treatment modalities. The evaluation of their efficacy has mostly relied on criteria based on size variations, which do not take into account tumor viability and metabolism, and thus may not be relevant. These techniques may be especially effective when performed as first-line therapies, in patients with non-major liver involvement (<75%) and with hypervascular metastases. Finally, studies exploring their combination with systemic therapies are ongoing.

The impact of extrahepatic disease among patients undergoing liver-directed therapy for neuroendocrine liver metastasis

INTRODUCTION

Management of neuroendocrine liver metastasis (NELM) in the presence of extrahepatic disease (EHD) is controversial. We sought to examine outcomes of patients undergoing liver-directed therapy (resection, ablation, or both) for NELM in the presence of EHD using a large international cohort of patients.

METHODS

612 patients who underwent liver-directed therapy were identified from eight institutions. Postoperative outcomes, as well as and overall (OS) were compared among patients with and without EHD.

RESULTS

Most primary tumors were located in the pancreas (N = 254;41.8%) or the small bowel (N = 188;30.9%). Patients underwent surgery alone (N = 471;77.0%), ablation alone (N = 15;2.5%), or a combined approach (N = 126;20.6%). Patients with EHD had more high-grade tumors (EHD: 44.4% vs no EHD: 16.1%; P < 0.001). EHD was often the peritoneum (N = 29;41.4%) or lung (N = 19;27.1%). Among 70 patients with EHD, 20.0% (N = 14) underwent concurrent resection for EHD. After median follow-up of 51 months, 174 (28.4%) patients died with a median OS of 140.4 months. Patients with EHD had a shorter median OS versus patients who did not have EHD (EHD: 87 months vs no EHD: not reached; P = 0.002). EHD was independently associated with an increased risk of death (HR: 2.56, 95%CI 1.16-5.62; P = 0.02).

CONCLUSION

Patients with NELM and EHD had more aggressive tumors, conferring a twofold increased risk of death. Surgical treatment of NELM among patients with EHD should be individualized.

Safety and efficacy of doxorubicin-eluting superabsorbent polymer microspheres for the treatment of liver metastases from neuroendocrine tumours: preliminary results

Background

The aim of the study was to retrospectively evaluate the symptom control, tumour response, and complication rate in patients with liver-predominant metastatic neuroendocrine tumours treated with transarterial chemoembolization using doxorubicin-eluting superabsorbent polymer (SAP) microspheres.

Patients and methods

Patients with neuroendocrine liver metastases who underwent hepatic transarterial chemoembolization using doxorubicin-eluting SAP-microspheres (50–100 μm Hepasphere/Quadrasphere Microsphere® particles, Merit Medical, South Jordan, Utah, USA) were included in this study. Pre-and post-procedure imaging studies were evaluated to assess short and intermediate-term tumour response using modified RECIST criteria. Symptom relief and procedure-related complications were evaluated.

Results

A total of 27 embolization procedures were performed on 17 patients. Twelve of 17 patients (70%) were symptomatic, including carcinoid syndrome (n = 8) and severe, uncontrollable hypoglycemia (n = 4). Eight of 12 patients (67%) had complete symptom relief, and the remaining 4 (33%) had partial relief. One patient developed ischemic cholecystitis (6%). No other hepatobiliary complications occurred. Short-term and intermediate-term imaging follow-up was available for 15/17 patients (88%) and 12/14 patients (86%) respectively. At short-term follow-up (< 3 months), 14 patients (93%) showed partial response and the remaining patient had progressive disease (7%). At intermediate-term imaging follow-up (> 3 months), partial response, stable disease and progressive disease were found respectively in 7 (58%), 3 (25%) and 2 (17%) patients.

Conclusions

Chemoembolization with doxorubicin-eluting SAP-microspheres is a safe and effective treatment option for neuroendocrine liver metastases and is associated with a low complication rate. In particular, no clinically evident liver necrosis or bile duct complications were encountered.

Conventional versus Drug-Eluting Bead Transarterial Chemoembolization for Neuroendocrine Tumor Liver Metastases

PURPOSE

To compare outcomes of conventional transarterial chemoembolization with drug-eluting bead (DEB) chemoembolization for treatment of neuroendocrine tumor liver metastases.

MATERIALS AND METHODS

This single-center, retrospective study evaluated 177 transarterial chemoembolization treatments (78 conventional chemoembolization treatments using ethiodized oil-based cisplatin, mitomycin C, and doxorubicin and 99 DEB chemoembolization treatments using doxorubicin-loaded 100-300 μm DEBs) from 2012 to 2015. Hepatic disease distribution was 93% bilobar for both groups with largest lesion size 5.0 cm ± 2.7. No difference was noted in regard to lesion size or distribution, carcinoid syndrome, or pancreastatin production. Clinical outcomes including complications; liver function tests (LFTs); and radiologic (modified Response Evaluation Criteria in Solid Tumors), biochemical (pancreastatin levels), and symptomatic responses were evaluated at 1-month follow-up.

RESULTS

Higher symptomatic response (complete and partial) was identified with conventional transarterial chemoembolization compared with DEB chemoembolization (47% vs 30%; P < .05). Patients receiving DEB transarterial chemoembolization experienced lower elevation of LFTs (aspartate aminotransferase, 39 U/L vs 122 U/L; alanine aminotransferase, 20 U/L vs 93 U/L; bilirubin, 0.001 mg/dL vs 0.123 mg/dL; P < .05) and less postembolization syndrome (50% vs 67%; P < .05). Patients undergoing first-time DEB transarterial chemoembolization had lower periprocedural octreotide maximum rate requirements (58 μg/h vs 66 μg/h; P < .05). No difference was observed in biochemical (P = .60) or radiologic (P < .20) responses.

CONCLUSIONS

Conventional transarterial chemoembolization yields better symptomatic response and may be preferred for patients experiencing carcinoid symptoms. DEB transarterial chemoembolization, with lower LFT elevations and postembolization syndrome incidence, may be preferred for patients with poor liver function.

Elevated Alkaline Phosphatase Prior to Transarterial Chemoembolization for Neuroendocrine Tumors Predicts Worse Outcomes

INTRODUCTION

We hypothesized that an elevated preoperative alkaline phosphatase (AP) predicted worse outcomes for patients undergoing transarterial chemoembolization (TACE) for neuroendocrine tumor (NET) liver metastases.

METHODS

We reviewed all patients who underwent TACE for metastatic NET between 2009 and 2013. Survival was evaluated using preprocedure variables.

RESULTS

One hundred and nine patients underwent 210 TACE procedures. The average age was 57.7 years (range 20-78). Primary sites included pancreas (N = 20), other gastrointestinal (N = 52), lung (N = 9), and unknown (N = 28). The tumor was grade 1 in 68 (62 %), grade 2 in 21 (19 %), and grade 3 in 3 (3 %). Extrahepatic disease was present in 54 (50 %) and greater than 50 % hepatic tumor burden by imaging in 63 (58 %). Elevated bilirubin occurred in 8 (7 %), elevated AP in 22 (20 %), elevated ALT in 21 (19 %), and elevated AST in 41 (38 %). Univariate predictors included tumor grade (43 vs 27 vs 21 months, p = 0.015), hepatic tumor burden (59 vs 37 months, p = 0.009), and elevated AP (59 vs 23 months, p < 0.001). On multivariate analysis, only elevated AP (p = 0.001) predicted worse survival.

CONCLUSIONS

Elevated AP prior to TACE for metastatic NET portends a worse survival outcome, even more so than tumor grade or extent of hepatic disease.

Liver transplantation for the treatment of neuroendocrine liver metastases

Neuroendocrine neoplasms represent a heterogeneous group of cancers arising from a variety of neuroendocrine cell types. In general, these tumors (NET) are asymptomatic and are discovered late once metastatic disease is present (40-80%). The liver is the most common organ involved when metastases occur (40-93%), followed by bone (12-20%) and lungs (8-10%). A number of different therapeutic options are available for patients with hepatic metastases including surgical resection, transplantation, transarterial chemoembolization, radiofrequency and microwave ablation, radioembolization (Y90), chemotherapy, somatostatin analogues and molecular targeted therapies. Surgical resection is still considered the treatment of choice and provides excellent disease control with an overall survival of 47-92%. Liver transplantation has been advocated in selected patients with bilateral unresectable symptomatic liver metastases. The aim of this study is to review the existing literature emphasizing on the role of transplantation to treat patients with liver metastases from NET.

Aggressive Locoregional Treatment Improves the Outcome of Liver Metastases from Grade 3 Gastroenteropancreatic Neuroendocrine Tumors

Grade 3 (G3) gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are rare, and there is no report specifically dealing with patients of liver metastases from G3 GEP NETs.From January 2004 to January 2014, 36 conservative patients with G3 GEP NET liver metastases were retrospectively identified from 3 hepatobiliary centers in China. The clinical features and treatment outcomes were analyzed.Aggressive locoregional treatments (LT, including cytoreductive surgery, radiofrequency ablation, and liver-directed intra-arterial intervention) and systemic therapy (ST) were introduced separately or combined, with 26 (72%) patients receiving resection of primary tumor and/or hepatic metastases, 12 patients receiving non-surgical locoregional interventions (NSLRIs), and 22 patients receiving certain kind of STs. Median overall survival (OS) was 20.0 months (95% confidence interval [CI]: 8.9-31.1 months) and survival rates were 62.6%, 30.1%, and 19.8%, at 1, 3, and 5 years, respectively. The median OS was 9.0 months (95%CI: 3.3-14.7 months) for patients receiving only STs (n = 6), 19 months (95%CI: 1.3-36.8 months) for patients receiving LT followed by STs (n = 16), and 101 months (95%CI: 0.0-210.2 months) for patients receiving only LT (n = 12). Moreover, compared with those receiving only ST or best supportive care, patients given certain types of LTs had higher rates of symptom alleviation (3/8 versus 20/23). On univariate analysis, positive prognostic factors of survival were pancreatic primary tumor (P = 0.013), normal total bilirubin level (P = 0.035), receiving surgery (P = 0.034), receiving NSLRI (P = 0.014), and sum of diameters of remnant tumor < 5 cm (P = 0.008). On multivariate analyses, pancreatic primary tumor (P = 0.015), normal total bilirubin level (P = 0.002), and sum of diameters of remnant tumor < 5 cm (P = 0.001) remained to be independent prognostic factors.For patients with G3 GEP NET liver metastases, aggressive LTs may improve clinical outcomes. Larger studies with prospective design are warranted to consolidate these results, and to discover the most appropriate seletion criteria for patients to undergo different kinds of aggressive LTs and to find the most effective combinations, with or without ST.

Liver-directed therapy for neuroendocrine liver metastases

Abstract: 

Neuroendocrine tumors are relatively uncommon neoplasms presenting with a wide spectrum of clinical behavior. Many patients may present with or develop liver metastases from neuroendocrine tumors, which significantly influences prognosis and the potential for symptoms. Data suggest that some patients may have symptomatic relief and oncologic benefit from liver-directed therapy for neuroendocrine tumor metastases. Surgical resection, tumor ablation, transarterial therapy such as bland embolization, chemoembolization and radioembolization, as well as liver transplantation have been studied as liver-directed therapies. Data continue to emerge to help guide selection of treatment modality for an individual patient. The spectrum of behavior of neuroendocrine metastases and heterogeneity in the literature are a challenge to arriving at cohesive recommendations for all patients.

Liver transplantation for metastatic neuroendocrine tumors

The ideal management of NET must be addressed on a case-by-case basis, with consideration given to patient factors, disease burden, and clinical tumor activity. Outcome improvement for LT in the setting of metastatic disease requires better characterization of the biological behavior of NETs and further identification of factors to be included in the selection criteria. Box 3 summarizes the many areas that have been, and are currently, undergoing investigation. LT as an attempt for cure rather than palliation is a justified treatment option for well-selected patients with metastatic neuroendocrine tumors of the pancreas and GI system. Optimization of pretransplantation staging and patient management algorithms, patient selection, and posttransplant management options are areas that need to be better defined. Further investigations for defining reproducible prognostic factors, consistent histopathologic evaluation, and uniform preoperative staging and site-specific data are needed. With the advancement of newer treatment modalities, it is necessary to define the role of LT along with the optimal perioperative management of existing and recurrent disease.

Therapeutic strategies for neuroendocrine liver metastases

Patients who have neuroendocrine tumors frequently present with liver metastases. A wide panel of treatment options exists for these patients. Liver resection with curative intent achieves the best long-term results. Highly selected patients may be considered for liver transplantation. Substantial recurrence rates reported after surgical approaches call for neoadjuvant and adjuvant concepts. Liver-directed, locally ablative procedures are recommended for patients with limited, nonresectable tumor burden. Angiographic liver-directed techniques, such as transarterial embolization, transarterial chemoembolization, and selective internal radiotherapy, offer excellent palliation for patients with liver-predominant disease. Peptide receptor radionuclide therapy is a promising palliative procedure for patients with hepatic and/or extrahepatic metastases. The efficacy of these treatment options needs to be evaluated in randomized trials. Somatostatin analogues have demonstrated effectiveness not only for symptomatic relief in patients with secreting tumors but also for the control of proliferation in small intestinal neuroendocrine tumors and most recently also in those originating from the pancreas. Chemotherapy is an option mainly for those with pancreatic neuroendocrine tumors and high-grade tumors irrespective of the origin. Novel drugs targeting specific pathways within the tumor cell have produced improved progression-free survival compared with placebo in patients with pancreatic neuroendocrine tumors. Despite such a diverse armamentarium, there is uncertainty with regard to the optimal treatment regimens. Newly introduced molecular-based markers, along with the conduction of clinical trials comparing the efficacy of treatment modalities, offer a chance to move the treatment of neuroendocrine tumor disease toward personalized patient care. In this report, the authors review the approaches for treatment of neuroendocrine liver metastases, identify shortcomings, and anticipate future perspectives. Furthermore, clinical practice recommendations are provided for currently available treatment options. Although multiple modalities are available for the treatment of neuroendocrine liver metastases, optimal management is unclear. The current knowledge pertaining to these treatment options is analyzed.

New trends in the multidisciplinary treatment of liver tumors

The authors report on new trends in the multidisciplinary treatment of liver tumors from the 3rd Interdisciplinary Treatment of Liver Tumors Congress in Essen, Germany. Novel aspects of molecular target-oriented therapies of hepatocarcinoma were reported, such as the current position of radiofrequency and microwave ablation of tumors compared with the new electroporation technique. State-of-the-art and new surgical trends in cholangiocarcinoma treatment were also discussed. The correlation of the biological behavior involved in the differentiation of melanomas with the treatment of liver metastasis was better defined. The role of neoadjuvant chemotherapy and combined strategies for colorectal liver metastasis were focused on intra-arterial therapeutic options. New data on neuroendocrine tumor liver metastases were also shared, leading to a better orientation for patient selection for surgical treatment.