Resection versus transplantation for liver metastases from neuroendocrine tumors

Liver Transplant for Patients With Neuroendocrine Tumor: A Report of 2 Exceptional Cases and Literature Review

Patients with neuroendocrine tumors with unresec-table liver involvement can benefit from liver transplant. There is a specific set of guidelines for neuroendocrine tumors with liver metastasis that involve less than 50% of the liver. However, beyond those guidelines, there are reports of exceptional criteria patients who benefited from liver transplant. Here, we present 2 unusual cases of patients with exceptional circumstances and with neuroendocrine tumors who underwent liver transplant. The first case describes a patient with an extremely rare neuroen-docrine tumor of the proximal common bile duct that caused liver biliary cirrhosis. The patient underwent tumor resection and liver transplant concurrently. The second case describes a patient with a neuroendocrine tumor of unknown primary origin with more than 50% hepatic involvement who received a liver transplant after downstaging. In our center, patients with unresectable hepatic metastases from neuroendoc-rine tumors are currently selected for liver transplant based on well-established criteria. However, these 2 cases did not meet the criteria for consideration of liver transplant; thus, multidisciplinary team sessions were held to discuss these 2 cases. After a period of nonsurgical treatment and evaluation of the tumor behavior, we selected the patients as candidates for liver transplant based on the favorable tumor behavior and favorable response to treatment. For both patients, we did not observe any signs of tumor recurrence during follow-up. The outcomes were acceptable, and the patients tolerated treatment well. Considering the favorable tumor pathology (G1 phase and low Ki67 index), we suggest that more studies should be conducted to evaluate the outcomes of patients with low-grade tumors and that the criteria for patients with low-grade tumors could be extended based on such future data.

Orchestrating Treatment Modalities in Metastatic Pancreatic Neuroendocrine Tumors-Need for a Conductor

Simple Summary

Pancreatic neuroendocrine tumors (pNET) are a heterogeneous and challenging entity, and today’s guidelines offer a variety of treatment modalities, while surgery has a clear role for patients with resectable tumors and early stages, advanced, or metastatic pNET may benefit from treatments that were evaluated in randomized controlled studies during the last year. With this review, we aim to provide an updated view on treatment options for metastatic pNET.

Abstract

Pancreatic neuroendocrine tumors (pNETs) are a vast growing disease. Over 50% of these tumors are recognized at advanced stages with lymph node, liver, or distant metastasis. An ongoing controversy is the role of surgery in the metastatic setting as dedicated systemic treatments have emerged recently and shown benefits in randomized trials. Today, liver surgery is an option for advanced pNETs if the tumor has a favorable prognosis, reflected by a low to moderate proliferation index (G1 and G2). Surgery in this well-selected population may prolong progression-free and overall survival. Optimal selection of a treatment plan for an individual patient should be considered in a multidisciplinary tumor board. However, while current guidelines offer a variety of modalities, there is so far only a limited focus on the right timing. Available data is based on small case series or retrospective analyses. The focus of this review is to highlight the right time-point for surgery in the setting of the multimodal treatment of an advanced pancreatic neuroendocrine tumor.

Multimodal Management of Grade 1 and 2 Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (p-NETs) are rare tumors with a recent growing incidence. In the 2017 WHO classification, p-NETs are classified into well-differentiated (i.e., p-NETs grade 1 to 3) and poorly differentiated neuroendocrine carcinomas (i.e., p-NECs). P-NETs G1 and G2 are often non-functioning tumors, of which the prognosis depends on the metastatic status. In the localized setting, p-NETs should be surgically managed, as no benefit for adjuvant chemotherapy has been demonstrated. Parenchymal sparing resection, including both duodenum and pancreas, are safe procedures in selected patients with reduced endocrine and exocrine long-term dysfunction. When the p-NET is benign or borderline malignant, this surgical option is associated with low rates of severe postoperative morbidity and in-hospital mortality. This narrative review offers comments, tips, and tricks from reviewing the available literature on these different options in order to clarify their indications. We also sum up the overall current data on p-NETs G1 and G2 management.

Expanding Indications for Liver Transplant: Tumor and Patient Factors

During the past few decades, liver transplant has developed from a high-mortality procedure to an almost routine procedure with good survival outcomes. The development of living donor liver transplant has increased the availability of liver grafts, and the scope of indications for liver transplant has been expanding ever since. The aim of this review is to provide an overview of such an expansion of scope. Various criteria have been proposed to expand the eligibility of patients with hepatocellular carcinoma exceeding the Milan criteria for liver transplant. Furthermore, liver transplant is increasingly performed as a treatment modality for cholangiocarcinoma, neuroendocrine liver metastasis and colorectal liver metastasis. The number of elderly patients receiving liver transplant is on the rise. Combined organ transplantation has also been adopted to treat patients with multiple organ failure. Going forward, further development of preoperative noninvasive predictors in tumor, patient and even donor factors is needed to identify patients at risk of poor outcomes and hence optimize patient management.

Recent developments and ongoing trials in transplant oncology

Over the past two decades since the introduction of the Milan criteria, the field of transplant oncology has undergone a rapid development with a rising proportion of liver transplantations being performed for oncological indications. For many patients with liver tumours, transplantation represents the only chance for cure. However, many challenges remain, such as the adequate patient selection, management of post-transplant recurrence and refinement of neoadjuvant treatment protocols. This review provides an overview of the current state of the art of liver transplantation for oncological indications such as hepatocellular carcinoma, cholangiocarcinoma, colorectal liver metastasis and metastatic neuroendocrine tumours. We also summarize the ongoing research and explore future trends. Clinical trials are currently studying new diagnostic modalities, innovative pharmacological treatments, novel surgical techniques, downstaging regimens and new indications for liver transplantation. These emerging results will continue to shape the field of transplant oncology and provide us with the necessary tools to better select, treat and follow patients with liver tumours qualifying for liver transplantation.

Treatment of Liver Metastases from Midgut Neuroendocrine Tumours: A Systematic Review and Meta-Analysis

Strong evidence comparing different treatment options for liver metastases (LM) arising from gastroenteropancreatic neuroendocrine tumours (GEP-NET) is lacking. The aim of this study was to determine which intervention for LMs from GEP-NETs shows the longest overall survival (OS). A systematic search was performed in MEDLINE, Embase and the Cochrane Library in February 2018. Studies reporting on patients with LMs of any grade of sporadic GEP-NET comparing two intervention groups were included for analysis. Meta-analyses were performed where possible. Eleven studies, with a total of 1108, patients were included; 662 patients had LM from pancreatic NETs (pNET), 164 patients from small-bowel NETs (SB-NET) and 282 patients of unknown origin. Improved 5-year OS was observed for surgery vs. chemotherapy (OR .05 95% CI [0.01, 0.21] p < 0.0001), for surgery vs. embolization (OR 0.18 95% CI [0.05, 0.61] p = 0.006) and for LM resection vs. no LM resection (OR 0.15 95% CI [0.05, 0.42] p = 0.0003). This is the largest meta-analysis performed comparing different interventions for LMs from GEP-NETs. Despite the high risk of bias and heterogeneity of data, surgical resection for all tumour grades results in the longest overall survival. Chemotherapy and embolization should be considered as an alternative in case surgery is not feasible.

Liver Resection for Neuroendocrine Tumor Liver Metastases Within Milan Criteria for Liver Transplantation

BACKGROUND

The role of liver transplant (LT) for neuroendocrine liver metastasis (NELM) has not been completely defined. While international guidelines included LT as a potential treatment for highly selected patients with advanced NELM, recently, LT has been proposed as an alternative curative treatment for NELM for patients meeting restrictive criteria (Milan criteria).

METHODS

Using a multi-institutional cohort of patients undergoing liver resection for NELM, the long-term outcomes of patients meeting Milan criteria (resected NET drained by the portal system, stable disease/response to therapies for at least 6 months, metastatic diffusion to < 50% of the total liver volume, a confirmed histology of low-grade, and ≤ 60 years) were investigated.

RESULTS

Among the 238 patients included in the study, 28 (12%) patients met the Milan criteria for LT with a 5-year OS of 83%. Furthermore, among patients meeting Milan criteria, subsets of patients with favorable clinic-pathological characteristics had 5-year OS rates greater than 90% including G1 patients (5-year OS, 92%), patients undergoing minor liver resection (5-year OS, 94%), patients with low number of NELM (1-2 NELM), and small tumor size (< 3 cm) (for both groups of patients, 5-year OS, 100%).

CONCLUSIONS

In our series, only 12% of patients met Milan criteria, and the 5-year OS after liver resection for this small selected group of patients was comparable with that reported in the literature for patients undergoing LT for NELM within Milan criteria. While LT might be the optimal treatment for patients with unresectable NELM, surgical resection should be the first option for patients with resectable NELM.

Surgical management of neuroendocrine tumor-associated liver metastases: a review

Liver metastasis is common among patients who suffer from neuroendocrine tumors (NETs). Radical surgery is the standard treatment whenever possible but there is still controversies concerning the treatment strategies such as resection of the primary, role of debulking surgery, liver transplantation (LT) and neoadjuvant or adjuvant therapies. This article aims to review the current evidence available, together with some latest updates, focusing on the surgical management.

Con: Liver transplantation for expanded criteria malignant diseases

Organ shortage requires policies and guidelines to aid organ allocation along the principles of urgency or utility. Identifying patients with significant benefit and withholding liver transplantation (LT) from patients too sick for transplantation are ongoing challenges, in particular in patients with malignancies. An arbitrary threshold of >50% 5-year overall survival (OS) is broadly considered a minimum standard for LT. In patients transplanted for intrahepatic cholangiocarcinoma (iCC), this was only achieved in select cases and when the tumor had a diameter of <2 cm. In patients with extrahepatic and hilar cholangiocarcinoma (CCC), strict selection criteria and combined preoperative radiotherapy/chemotherapy according to the Mayo protocol showed that acceptable longterm results can be achieved in a single high-volume center but are difficult to repeat elsewhere. Furthermore, only rigorously selected patients with neuroendocrine tumors (NETs) meeting the NET Milan criteria adopted by United Network for Organ Sharing can also have >50% 5-year OS. A prospective study in patients with unresectable colorectal cancer metastases in the liver has shown promising OS rates, but further prospective trials are warranted. Current evidence shows that none of the proposed expanded malignant criteria justify deviation of scarce donor organs to patients with hilar CCC, iCC > 2 cm, metastatic NET beyond NET Milan criteria, or metastatic colorectal cancer (CRC) outside clinical trials. Liver Transplantation 24 104-111 2018 AASLD.

The place of liver transplantation in the treatment of hepatic metastases from neuroendocrine tumors: Pros and cons

Liver metastases occur in nearly half of NET patients (MNETs) and heavily affect prognosis, with 5-yr. OS around 19-38%. Although it is difficult to show outcome differences for available treatments, due to the long course of disease, surgery for MNETs remains the most effective option in terms of survival and symptom control. Since MNETs frequently present as an oligo-metastatic, liver-limited disease, unresectable in 80% of cases, liver transplantation (LT) has emerged as a potential curative treatment. Nevertheless, experience with LT for MNETs is limited and burdened by highly heterogeneous outcomes and significant recurrence rate, mostly explained by the variability of selection criteria. Several prognostic factors have been identified: extended surgery on primary tumor associated to LT, elderly patients, pancreatic primary (pNET), extensive liver involvement, poorly differentiated tumors, high Ki67 levels and short wait time to LT. A proper patients' selection based on these data (Milan NET criteria) allows a significant survival advantage over non-transplant strategies, with excellent outcomes in recent series (69-97.2% 5-yr. OS) as opposed to patients undergoing non-surgical treatments (34-50.9%). Evidence indicates LT as the best option for selected patients with MNETs. The use of organs for MNETs is therefore justified.

Decision Making for Selection of Transarterial Locoregional Therapy of Metastatic Neuroendocrine Tumors

Transarterial locoregional therapies (LRTs) are indispensable components of the modern interventional oncologic therapy of liver-dominant metastatic neuroendocrine tumors (NETs). The scope of available LRTs and their nuanced differences mandates a thorough understanding of their relative applicability and effectiveness in certain clinical circumstances to prescribe appropriate, patient-specific, image-guided therapy. This article aims to provide an overview of transarterial LRT options for liver-dominant metastatic NETs and therapy selection by reviewing procedure types, their advantages and disadvantages, and comparative efficacy in common case scenarios.

Rectal Carcinoid Tumor With Liver Metastases Treated by Local Excision and Orthotopic Liver Transplant With Long-term Follow-up

In patients affected by unresectable liver metastases from neuroendocrine tumor, liver transplant represents currently the only realistic chance for cure. The first attempt to establish selection criteria for liver transplant in patients affected by neuroendocrine tumor liver metastases was made by Mazzaferro and associates in 2007. We report the case of a 46-year-old man who came to our institution in 2006 with right upper quadrant abdominal pain. Diagnosis of rectal neuroendocrine tumor with bilobar liver nodules was made; the patient underwent transanal local resection. A liver biopsy confirmed the metastatic nature of the hepatic lesion, showing a low-grade neuroendocrine tumor (G1, proliferation index Ki-67 <2%). The patient underwent 2 sessions of transarterial chemoembolization that resulted in stable disease. Afterward, the patient underwent a liver transplant, using the piggyback technique without a venous-venous bypass. His postoperative course was uneventful. The patient has been disease-free for 3 years. Posttransplant treatment has played a key role in increasing the overall survival of the patient and assuring him a good quality of life. He died 9 years (102 mo) after liver transplant.

Gastroenteropancreatic neuroendocrine tumors: recommendations of Turkish multidisciplinary neuroendocrine tumor study group on diagnosis, treatment and follow-up

Gastroenteropancreatic neuroendocrine tumors (GEPNETs) are a relatively rare, heterogeneous group of diseases in which important advances have been observed in the diagnosis and treatment as well as in our understanding of the biology and genetics of the disease in recent years. Given the insufficient scientific data available on evidence-based management of GEPNETs and the differences in circumstances in individual countries, a multidisciplinary study group was established to provide guidelines for the management of GEPNETS. This study group consisted of a medical oncologist, endocrinologist, surgeon, pathologist, gastroenterologist, and a nuclear medicine specialist, who aimed to prepare a practical guide in the light of existing scientific data and international guidelines, to be used in common clinical practice.

The Long-Term Benefit of Liver Transplantation for Hepatic Metastases From Neuroendocrine Tumors

Selection criteria and benefit of liver transplantation for hepatic metastases from neuroendocrine tumors (NETs) remain uncertain. Eighty-eight consecutive patients with metastatic NETs eligible for liver transplantation according to Milan-NET criteria were offered transplant (n = 42) versus nontransplant options (n = 46) depending on list dynamics, patient disposition, and age. Tumor burden between groups did not differ. Transplant patients were younger (40.5 vs. 55.5 years; p < 0.001). Long-term outcomes were compared after matching between groups made on multiple Cox models adjusted for propensity score built on logistic models. Survival benefit was the difference in mean survival between transplant versus nontransplant options. No patients were lost or died without recurrence. Median follow-up was 122 months. The transplant group showed a significant advantage over nontransplant strategies at 5 and 10 years in survival (97.2% and 88.8% vs. 50.9% and 22.4%, respectively; p < 0.001) and time-to-progression (13.1% and 13.1% vs. 83.5% and 89%; p < 0.001). After adjustment for propensity score, survival advantage of the transplant group was significant (hazard ratio = 7.4; 95% confidence interval (CI): 2.4-23.0; p = 0.001). Adjusted transplant-related survival benefit was 6.82 months (95% CI: 1.10-12.54; p = 0.019) and 38.43 months (95% CI: 21.41-55.45; p < 0.001) at 5 and 10 years, respectively. Liver transplantation for metastatic NETs under restrictive criteria provides excellent long-term outcome. Transplant-related survival benefit increases over time and maximizes after 10 years.

Long term results of hepatic resection or orthotopic liver transplantation in patients with liver metastases from gastrointestinal neuroendocrine tumors

Hepatic metastases are one of the most important prognostic factors for survival among patients affected by gastrointestinal neuroendocrine tumors (NETs). The present study aims to evaluate the impact of surgery, including hepatic resection or orthotopic liver transplantation (OLT), on the outcome of patients affected by hepatic metastases from NETs, in terms of overall survival (OS). In this multicentric retrospective study, data was collected on 26 patients, who underwent surgery for hepatic metastases from NETs in two Italian University Clinics between January 1990 and December 2012; of which, 22 patients underwent hepatic resective surgery and 4 patients OLT. Hepatic metastases were synchronous in the 53.8% of cases and metachronous in the 46.2% of cases. The median number of resected hepatic metastases was 3. Surgical radicalness (R0) was reached in the 84.6% of cases. In total, 57.7% of patients had a recurrence, 66.7% of which were intra- and 33.3% extra-hepatic. The OS of patients that underwent hepatic resections and OLT was 44.9% [95% confidence interval (CI95), 26.0-77.7%] and 50% (CI95, 12.5-100.0%) at 5 years, respectively. Although the data regarding the survival of patients receiving surgery for hepatic metastases from NETs are encouraging, randomized clinical trials are necessary to more adequately evaluate the effect of surgery on survival of this group of patients.

Liver transplantation for metastatic neuroendocrine tumors: Outcomes and prognostic variables

BACKGROUND

Patient selection for liver transplantation for metastatic neuroendocrine tumors remains a topic of debate. There is no established MELD exception, making it difficult to obtain donor organs.

METHODS

A multicenter database was created assessing outcomes for liver and multivisceral transplantation for metastatic neuroendocrine tumors and identifying prognostic factors for survival. Demographic, transplant, primary tumor site and management, pathology, recurrent disease and survival data were collected and analyzed. Survival probabilities were calculated using the Kaplan-Meier method.

RESULTS

Analysis included 85 patients who underwent liver transplantation November 1988-January 2012 at 28 centers. One, three, and five-year patient survival rates were 83%, 60%, and 52%, respectively; 40 of 85 patients died, with 20 of 40 deaths due to recurrent disease. In univariate analyses, the following were predictors of poor prognosis: large vessel invasion (P < 0.001), extent of extrahepatic resection at liver transplant (P = 0.007), and tumor differentiation (P = 0.003). In multivariable analysis, predictors of poor overall survival included large vessel invasion (P = 0.001), and extent of extrahepatic resection at liver transplant (P = 0.015).

CONCLUSION

In the absence of poor prognostic factors, metastatic neuroendocrine tumor is an acceptable indication for liver transplantation. Identification of favorable prognostic factors should allow assignment of a MELD exception similar to hepatocellular carcinoma.

Liver transplantation for metastatic neuroendocrine tumors

Neuroendocrine tumors are a heterogeneous group of rare epithelial tumors. Most of them are metastatic at the time of initial diagnosis. Liver transplantation (LT) has been proposed in selected patients with diffuse liver involvement. Rationale for LT in this indication is based on the frequently indolent nature of neuroendocrine tumors, the propensity for liver-only metastasis and the high rate of intrahepatic recurrence after resection. However, indications for LT for neuroendocrine liver metastases remain controversial, and patient selection criteria is still a matter of debate. The aim of this review is to summarize data regarding LT for neuroendocrine liver metastases by answering frequently asked questions about this issue.

Curative versus palliative surgical resection of liver metastases in patients with neuroendocrine tumors: a meta-analysis of observational studies

BACKGROUND

The role of surgical therapy in patients with liver metastases from neuroendocrine tumors (NETs) is unclear. In this study, the results obtained with curative or palliative resection, by reviewing recent literature and performing a meta-analysis, were examined.

MATERIALS AND METHODS

A systematic review and meta-analysis of observational studies published between January 1990 and October 2013 were performed. Studies that evaluated the different survival between patients treated by curative or palliative surgical resection of hepatic metastases from NETs were considered. The collected studies were evaluated for heterogeneity, publication bias, and quality. To calculate the pooled hazard ratio (HR) estimate and the 95% confidence interval (95% CI), a fixed-effects model was applied.

RESULTS

After the literature search, 2,546 studies were found and, among 38 potentially eligible studies, 3 were considered. We did not find a significant longer survival in patients treated with curative surgical resection of hepatic metastases when compared to palliative hepatic resection HR 0.40 (95% CI: 0.14-1.11). In one study, palliative resection of hepatic metastases significantly increased survival when compared to embolization.

CONCLUSIONS

Curative and also palliative surgery of NETs liver metastases may improve survival outcome. However, further randomized clinical trials are needed to elucidate this argument.

Liver transplantation for neuroendocrine tumors: review of the literature and future perspectives

Liver transplantation for metastases of neuroendocrine tumors is still a subject of controversial discussion. Over the years, more and more data have been collected to demonstrate that transplantation is feasible and contributes to long-term overall survival. Most data are of retrospective nature and, thus, it is difficult to draw definitive conclusions. Over the years, indications, surgical technique and perioperative care have improved. The most recent data have been collected prospectively and show a very favorable outcome in selected patients. Liver transplantation should be considered in patients with neuroendocrine liver metastases, but the decision needs to be made on an individual basis with particular emphasis on the tumor biology. In the future, we may need to work more with living organ donation and perhaps, especially in Europe, think about challenging the scoring system model of end-stage liver disease for this indication.

Role of surgery and transplantation in the treatment of hepatic metastases from neuroendocrine tumor

Neuroendocrine tumors (NET) are a heterogeneous group of cancers, with indolent behavior. The most common primary origin is the gastro-intestinal tract but can also appear in the lungs, kidneys, adrenals, ovaries and other organs. In general, NET is usually discovered in the metastatic phase (40%-80%). The liver is the most common organ involved when metastases occur (40%-93%), followed by bone (12%-20%) and lung (8%-10%).A number of different therapeutic options are available for the treatment of hepatic metastases including surgical resection, transplantation, ablation, trans-arterial chemoembolization, chemotherapy and somatostatin analogues. Recently, molecular targeted therapies have been used, usually in combination with other treatment options, to improve outcomes in patients with metastases. This article emphasizes on the role of surgery in the treatment of liver metastases from NET.

Liver transplant for neuroendocrine tumor metastatic to the liver: literature review and report of extirpation at 16-year recurrence

New information has demonstrated that there are few long-term disease-free survivors after a liver transplant for neuroendocrine tumors. All studies have limited follow-up to 10 years after a transplant. We present the case of a recurrent metastatic carcinoid in a patient 16 years after an orthotopic liver transplant. The subject initially presented with worsening chronic diarrhea, hypoglycemia, and confusion with massive hepatomegaly. The postoperative pathology report showed 80% to 90% of the liver tissue replaced by biopsy-proven synaptophysin-positive intrahepatic tumor with neuroendocrine differentiation. At the time of his liver transplant, he also underwent a distal pancreatectomy and splenectomy. Nuclear medicine tumor location studies, ultrasound, and computed tomography studies were performed at regular yearly intervals for 8 years on follow-up. Sixteen years after his orthotopic liver transplant, a retroperitoneal mass was detected showing neuroendocrine differentiation. Older studies focusing on an orthotopic liver transplant for highlighted clinical features would positively predict long-term survival. Older studies found the following features to be predictive of long-term survival in liver transplant for neuroendocrine tumors: age < 55 years, < 50% replacement of liver with metastatic neoplastic tissue and carcinoid type. These features were identified on multiple studies as positive predictors of disease-free survival. These studies were limited to, at most, 10-year follow-up. Newer studies have examined molecular features such as expression of E-cadherin and Ki-67 as positive predictors of long-term survival. However, no study has determined the full natural history of these tumors and for how long these patients should be followed. This anecdotal report highlights that late recurrence can occur.

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.

GEP-NETS update: a review on surgery of gastro-entero-pancreatic neuroendocrine tumors

The incidence of neuroendocrine tumors (NETs) has increased in the last decades. Surgical treatment encompasses a panel of approaches ranging from conservative procedures to extended surgical resection. Tumor size and localization usually represent the main drivers in the choice of the most appropriate surgical resection. In the presence of small (<2 cm) and asymptomatic nonfunctioning NETs, a conservative treatment is usually recommended. For localized NETs measuring above 2 cm, surgical resection represents the cornerstone in the management of these tumors. As they are relatively biologically indolent, an extended resection is often justified also in the presence of advanced NETs. Surgical options for NET liver metastases range from limited resection up to liver transplantation. Surgical choices for metastatic NETs need to consider the extent of disease, the grade of tumor, and the presence of extra-abdominal disease. Any surgical procedures should always be balanced with the benefit of survival or relieving symptoms and patients' comorbidities.

Management of patients with hepatic metastases from neuroendocrine tumors

Neuroendocrine tumors have a disposition toward metastasis to the liver. A range of treatment modalities for neuroendocrine liver metastases is available in the clinical arena, the indications for which depend on tumor characteristics such as patterns of metastasis, tumor grade, and anatomical origin. The complete surgical resection of liver deposits represents the only option with the intent to cure and is the gold standard approach, whereas cytoreductive resection (debulking) presents another surgical option aiming to ameliorate the symptoms and prolong survival. Liver transplantation is generally an accepted option for highly selected patients. For patients ineligible for radical surgery, liver-directed therapies-transarterial embolization/chemoembolization, selective internal radiotherapy, and local tumor ablation-present alternative strategies. Systemic therapies include peptide receptor radiotherapy, somatostatin analogues, cytotoxic chemotherapeutics, and novel molecularly targeted drugs. However, despite the variety of treatments available, there exists little evidence to guide optimal clinical practice with currently available data predominantly retrospective in nature. In this review, we discuss the diagnostic procedures that influence the trajectory of treatment of patients with neuroendocrine liver metastases before critically appraising the evidence pertaining to these therapeutic strategies.

Surgical treatment and survival in patients with liver metastases from neuroendocrine tumors: a meta-analysis of observational studies

Introduction. The role of hepatic resection in patients with liver metastases from gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is still poorly defined. Therefore, we examined the results obtained with surgical resection and other locoregional or systemic therapies by reviewing the recent literature on this topic. We performed the meta-analysis for comparing surgical resection of hepatic metastases with other treatments. Materials and Methods. In this systematic review and meta-analysis of observational studies, the literature search was undertaken between 1990 and 2012 looking for studies evaluating the different survivals between patients treated with surgical resection of hepatic metastases and with other surgical or nonsurgical therapies. The studies were evaluated for quality, publication bias, and heterogeneity. Pooled hazard ratio (HR) estimates and 95% confidence intervals (CI.95) were calculated using fixed-effects model. Results. We selected six studies in the review, five of which were suitable for meta-analysis. We found a significant longer survival in patients treated with hepatic resection than embolisation HR 0.34 (CI.95 0.21-0.55) or all other nonsurgical treatments HR 0.45 (CI.95 0.34-0.60). Only one study compared surgical resection with liver transplantation and meta-analysis was not feasible. Conclusions. Our meta-analysis provides evidence supporting the hypothesis that hepatic resection increases overall survival in patients with liver metastases from GEP-NETs. Further randomized clinical trials are needed to confirm these findings and it would be desirable to identify new markers to properly select patients for surgical treatment.

Treatment options for unresectable neuroendocrine liver metastases

Hepatic metastases develop in 85% of patients with gastroenteropancreatic neuroendocrine tumors. Radical surgery, which involves resection of the primary and liver metastases, is the mainstay of treatment, with 60-70% 5-year survival and 35% 10-year survival rates. However, less than 15% of neuroendocrine tumor liver metastases (NETLMs) are resectable, owing either to multifocality or the inability to preserve sufficient parenchyma following resection. This article deals with the therapeutic modalities available for nonresectable liver metastases, and the therapeutic options available for management of nonresectable NETLMs are discussed. Targeted therapies for NETLMs include hepatic artery embolization, transcatheter arterial chemoembolization, radiolabeled/drug-eluting microspheres, radiofrequency ablation, cryoablation and phenol injection. Hepatic artery embolization/transcatheter arterial chemoembolization is associated with 75-100% symptom relief and an objective tumor response varying from 33 to 80%. Other modalities, such as biotherapy, peptide receptor therapy and chemotherapy, target both the primary and metastatic disease. Their effects on NETLMs as a subgroup have not been evaluated. Various therapeutic options are available for the treatment of unresectable NETLMs. Most offer significant symptomatic relief, with only a few comparative studies showing survival benefit. Most of the available evidence is based on retrospective and prospective case series rather than randomized controlled trials. Well-designed studies on existing treatment modalities and the search for newer therapeutic options are required.

Surgical resection of hepatic metastases from neuroendocrine neoplasms: a systematic review

BACKGROUND

Neuroendocrine tumours (NET) most commonly metastasize to the liver. Hepatic resection of NET hepatic metastases (NETHM) has been shown to improve symptomology and survival.

METHODS

A systematic review of clinical studies before September 2010 was performed to examine the efficacy of hepatic resection for NETHM. As a secondary end-point, the impact of treatment on safety and symptomology were determined and prognostic variables were identified. The quality of each study was also assessed using predefined criteria incorporating 9 characteristics. Clinical outcome was synthesized through a narrative review with full tabulation of results of all included studies.

RESULTS

Twenty-nine included reported survival outcomes with a median 3-, 5- and 10-year overall survival of 83% (range, 63-100%), 70.5% (range, 31-100%), and 42% (range, 0-100%), respectively. The median progression-free survival (PFS) was 21 months (range, 13-46 months) and median 1-,3-,5- and 10-year PFS of 63% (range, 50-80 %), 32% (range, 24-69%), 29% (range, 6-66%) and 1% (range, 0-11%), respectively. Poor histologic grade, extra-hepatic disease and a macroscopically incomplete resection were associated with a poor prognosis. Studies reported a median rate of symptomatic relief from surgery in 95% of patients (range, 50-100%).

CONCLUSION

Hepatic resection for NETHM provides symptomatic benefit and is associated with favourable survival outcomes although the majority of patients invariably develop disease progression.

Liver transplantation as treatment in a massive metastasis from Gruber-Frantz pancreatic tumor: a case report

The Gruber-Frantz tumor or solid pseudopapillary tumor of the pancreas accounts for 1% to 2% of pancreatic tumors. It occurs more frequently among women between 20 and 40 years of age and in the Asian population. These tumors are of low malignant potential and show slow growth. The symptoms are subtle, the most striking being pain and an abdominal mass. The most common site is the pancreatic tail. The location and local invasion determine the surgical technique. With R0 resection, survival is 95% at 5 years. In 15% of cases metastatic disease appears, mostly in the liver. The treatment of liver metastases is surgical resection. In the case of multiple liver metastases, the treatment is controversial. QT has been used, as well as radiofrequency ablation, arterial embolization, and intraarterial chemotherapy. Herein we have described the case of a 44-year-old woman with massive liver metastases who did not respond to QT lines and underwent successful liver transplantation with survival free of recurrence at 1 year later. This is the first liver transplantation for a metastatic pancreatic pseudopapillary tumor in Spain and the second described in the literature.

Surgical treatment of neuroendocrine liver metastases

Management of Neuroendocrine liver metastases (NELM) is challenging. The presence of NELM worsens survival outcome and almost 10% of all liver metastases are neuroendocrine in origin. There is no firm consensus on the optimal treatment strategy for NELM. A systematic search of the PubMed database was performed from 1995-2010, to collate the current evidence and formulate a sound management algorithm. There are 22 case series with a total of 793 patients who had undergone surgery for NELM. The overall survival ranges from 46-86% at 5 years, 35-79% at 10 years, and the median survival ranges from 52-123 months. After successful cytoreductive surgery, the mean duration of symptom reduction is between 16-26 months, and the 5-year recurrence/progression rate ranges from 59-76%. Five studies evaluated the efficacy of a combination cytoreductive strategy reporting survival rate of ranging from 83% at 3 years to 50% at 10 years. To date, there is no level 1 evidence comparing surgery versus other liver-directed treatment options for NELM. An aggressive surgical approach, including combination with additional liver-directed procedures is recommended as it leads to long-term survival, significant long-term palliation, and a good quality of life. A multidisciplinary approach should be established as the platform for decision making.

Consensus recommendations for the diagnosis and management of well-differentiated gastroenterohepatic neuroendocrine tumours: a revised statement from a Canadian National Expert Group

Well-differentiated neuroendocrine tumours (nets-previously called "carcinoid tumours") are relatively rare tumours originating from the diffuse neuroendocrine system; they are found most often in the bronchial or gastrointestinal systems. In Canada, gastroenterohepatic NETS represent less than 0.25% of oncology cases. Because of the relative rarity of these tumours, diagnostic and therapeutic approaches vary and are often based on individual physician experience. A number of European and North American groups have developed consensus guidelines for the diagnosis and management of well-differentiated gastroenterohepatic NETS, and in 2006, Canadian consensus guidelines were published by a Canadian expert group. The updated and expanded current Canadian guidelines are based on a consensus meeting held in Paris, France, in 2008 and are based on the most current literature.

Therapeutic management of patients with gastroenteropancreatic neuroendocrine tumours

Patients with neuroendocrine tumours (NETs) are best managed in a specialist centre as part of a multidisciplinary team comprising gastroenterologists, oncologists, endocrinologists, gastrointestinal and hepatopancreaticobiliary surgeons, pathologists, nuclear medicine physicians and technicians, radiologists, specialist nurses, pharmacists, biochemists and dieticians. This should ideally be led by a clinician with experience and interest in NETs. Although the number of medical treatments and clinical trials has increased in the decade, there is still a lack of prospective randomised trials; thus, management is mainly based on limited often single-centre studies, although there are now formal guidelines based on consensus expert opinion. We have outlined the current optimal management of patients with NETs. We have reviewed therapeutic options including surgery, somatostatin analogues and other biotherapies and peptide receptor-targeted therapy. We have discussed the challenge in managing hepatic metastases including hepatic artery embolisation, ablation and orthotopic liver transplant. In addition, we have briefly reviewed the emerging therapies such as the mammalian target of rapamycin and angiogenic inhibitors and the newer somatostatin analogues.

Retransplantation for donor-derived neuroendocrine tumor

Although tumor transmission through liver transplantation (LT) is a rare occurrence, the consequences can be devastating, even when a very aggressive management approach is adopted. We report the case of a donor-derived small cell neuroendocrine tumor (NET) in a patient who underwent LT for cholangiocarcinoma. Despite locoregional therapy, chemotherapy and ultimately retransplantation, the patient died from metastases. The high grade nature of the NET was the most important determinant of prognosis in this case. Our experience suggests that retransplantation for donor-derived NET should only be considered when tumor biology is favorable.

Neuroendocrine Liver Metastases and Orthotopic Liver Transplantation: The US Experience

Liver transplantation remains a controversial therapy for Neuroendocrine liver metastases (NLM), with coflicting suvival data reported. The aim was to assess the evolution of outcomes for patients transplanted for NLM in the US, both before and after the introduction of the MELD scoring system in 2002. The UNOS/OPTN database was reviewed to identify patients diagnosed with NLM who subsequently underwent a liver transplantation from 1988 to March 2011 (n = 184); Patient survival was determined using Kaplan-Meier methods and log-rank tests, and cox regression analysis was performed, using SPSS 15.0 (SPSS, Inc, Chicago, IL). The overall NLM patient survivals in the pre-MELD era were 79.5%, 61.4%, and 49.2% at 1, 3, and 5 years, respectively. After the introduction of the MELD score, NET/NLM patients had improved overall patient survivals at 1, 3, and 5 years of 84.7%, 65%, and 57.8%. Patients transplanted after 2002 had an improved survival outcome. Notably, the overall patient survival for NET is not significantly different when compared to the outcomes of patients transplanted for HCC, in the current era. This progress acknowleges the significant improvement in outcomes for NLM patients after liver transplantation and the potential for further gain in the survival of otherwise nonsurgical, terminal patients.

Liver transplantation for primary or secondary endocrine tumors

Endocrine tumors comprise a heterogeneous group of rare neoplasms. Liver metastatic endocrine tumors (MET) are amenable to various therapeutic modalities including liver transplantation (LT). However, LT for MET remains controversial because of the lack of clear selection criteria. The purpose of this study based on thorough perusal of English and French literature since 1989 was to identify prognostic factors and propose recommendations for selecting patients most likely to benefit LT for primary and secondary endocrine tumors.

Liver transplantation and neuroendocrine tumors: lessons from a single centre experience and from the literature review

Neuroendocrine tumor (NET) metastases represent at this moment the only accepted indication of liver transplantation (LT) for liver secondaries. Between 1984-2007, nine (1.1%) of 824 adult LTs were performed because of NET. There were five well differentiated functioning NETs (four carcinoids and one gastrinoma), three well differentiated non functioning NETs and one poorly differentiated NET. Indications for LT were an invalidating unresectable tumor (4x), and/or a diffuse tumor localization (3x) and/or a refractory hormonal syndrome (5x). Median post-LT patient survival is 60.9 months (range 4.8-119). One-, 3- and 5-year actuarial survival rates are 88%, 77% and 33%; 1, 3 and 5 years disease free survival rates are 67%, 33% and 11%. Due to a more rigorous selection procedure, results improved since 2000; three out of five patients are alive disease-free at 78, 84 and 96 months. Review of these series together with a review of the literature reveals that results of LT for this oncological condition can be improved using better selection criteria, adapted immunosuppression and neo- and adjuvant surgical as well as medical treatment. LT should be considered earlier in the therapeutic algorithm of selected NET patients as it is the only therapy that can offer a cure.

Minute liver metastases from a rectal carcinoid: A case report and review

We here report a 43-year-old male patient with minute liver metastases from a rectal carcinoid. Hepatic nodules were diagnosed during surgery, although they were not diagnosed by preoperative computed tomography or ultrasound examination. The rectal carcinoid was resected together with liver metastases and the patient has had no disease recurrence for 5 years following postoperative treatment of hepatic arterial infusion chemotherapy (HAIC) using 5-fluorouracil (5-FU) and oral administration of 1-hexylcarbamoyl-5-fluorouracil (HCFU). In 2003, a health check examination indicated presence of occult blood in his stool. Barium enema study revealed a rectal tumor in the lower rectum and colonoscopy showed a yellowish lesion with a size of 30 mm in diameter. Pathological examination of the biopsy specimen indicated that the rectal tumor was carcinoid. Although preoperative imaging examinations failed to detect liver metastases, 2 min nodules were found on the surface of liver during surgery. A rapid pathological examination revealed that they were metastatic tumors from the rectal carcinoid. Low anterior resection was performed for the rectal tumor and the pathological report indicated that there were 4 metastatic lymph nodes in the rectal mesentery. The patient received treatment by HAIC using 5-FU plus oral administration of HCFU and survived for 5 years.

We also review world-wide current treatments and their efficacy for hepatic metastases of carcinoid tumors.

[Indications and operative procedures for neuroendocrine liver metastases]

Neuroendocrine malignancies encompass a variety of tumors that differ considerably in origin, hormonal activity, and biological behavior. Because of their rarity most therapeutic recommendations have been based on limited evidence from small retrospective series observing miscellaneous patient cohorts. Only in recent years proposals for TNM and histological grading systems have been elaborated that allow further stratification of patients suffering from these tumors. Especially patients with well and moderately differentiated neuroendocrine malignancies benefit from resection of liver metastases, improving the 5-year survival rate from <50% to 80%. Orthotopic liver transplantation can likewise improve survival in carefully selected patients. New developments in imaging modalities, intensive care treatment, and in liver surgery itself have broadened the selection of potentially resectable tumors.

Simultaneous pancreatectomy and liver transplantation: a single-institution experience

BACKGROUND

There is wide debate among transplant centres regarding the indications for liver transplantation (LT) in malignancy. We report a single-centre experience with simultaneous LT and total pancreatectomy or pancreaticoduodenectomy.

METHODS

We performed a retrospective review of a prospectively established database of patients who underwent simultaneous LT and total pancreatectomy or pancreaticoduodenectomy. We analysed demographics, indications, approach and outcomes.

RESULTS

Between 1991 and 2006, 11 patients (four male; median age 51 years) underwent simultaneous LT and total pancreatectomy (n = 4) or pancreaticoduodenectomy (n = 7). Indications included metastatic neuroendocrine tumour (n = 5), hepatocellular carcinoma (n = 2), metastatic periampullary adenocarcinoma (n = 1), periampullary adenocarcinoma with end-stage liver disease (ESLD) (n = 2) and intraductal papillary mucinous neoplasm with ESLD (n = 1). The three patients with ESLD had non-alcoholic steatohepatitis, primary sclerosing cholangitis or cryptogenic cirrhosis. Median postoperative length of stay was 31 days (21-110 days). Overall median survival was 101 months (95% confidence interval 70.6-131.4). One-year survival was 91%, 2-year 90%, 5-year 67% and 10-year 33%. Postoperative complications included: re-operation (n = 4); anastamotic leak (n = 2); abdominal abscess (n = 3), and organ rejection (n = 1).

CONCLUSIONS

We report a series of pancreatectomy or pancreaticoduodenectomy and simultaneous LT in patients with extensive malignancy or impending liver failure that prevented pancreatectomy. This series provides evidence that combined pancreatic resection and LT can be a strategy in both radical resections and cases with ESLD that would otherwise preclude operative intervention.

Liver resection versus other treatments for neuroendocrine tumours in patients with resectable liver metastases

BACKGROUND

Neuroendocrine tumours are tumours of cells, which possess secretory granules and originate from the neuroectoderm. While liver resection is generally advocated in patients with resectable liver metastases, recent studies have shown good survival in patients with disseminated neuroendocrine tumours who underwent thermal ablation using radiofrequency.

OBJECTIVES

To determine the benefits and harms of liver resection versus other treatments in patients with resectable liver metastases from gastro-entero-pancreatic neuroendocrine tumours.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded and LILACS until July 2008 for identifying the randomised trials.

SELECTION CRITERIA

We considered only randomised clinical trials (irrespective of language, blinding, or publication status) comparing liver resection (alone or in combination with radiofrequency ablation or cryoablation) versus other interventions (chemotherapy, hormonotherapy, or immunotherapy) and those comparing liver resection and thermal ablation (radiofrequency ablation or cryoablation) in patients with resectable liver metastases from neuroendocrine tumours for the review.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion.

MAIN RESULTS

We were unable to identify any randomised clinical trial suitable for inclusion in this review. We were also unable to identify any quasi-randomised studies, cohort studies, or case-control studies that could inform meaningfully.

AUTHORS' CONCLUSIONS

There is no evidence from randomised clinical trials comparing liver resection versus other treatments in patients with resectable liver metastases from gastro-entero-pancreatic neuroendocrine tumours. Liver resection appears to be the main stay curative treatment for neuroendocrine liver metastases based on non-randomised studies. Further randomised clinical trials comparing liver resection alone or in combination with chemoembolisation or radionuclide therapy are needed. Further randomised clinical trials comparing surgical resection and radiofrequency ablation in selected patients may also be appropriate.

Palliative cytoreductive surgery versus other palliative treatments in patients with unresectable liver metastases from gastro-entero-pancreatic neuroendocrine tumours

BACKGROUND

Neuroendocrine tumours are tumours of cells which possess secretory granules and originate from the neuroectoderm. While liver resection is generally advocated in patients with resectable liver alone metastases, the management of patients with liver metastases, which cannot be completely resected, is controversial.

OBJECTIVES

To determine if cytoreductive surgery is better than other palliative treatments in patients with liver metastases from gastro-entero-pancreatic neuroendocrine tumours, which cannot be completely resected.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and LILACS until July 2008 for identifying the randomised trials.

SELECTION CRITERIA

Only randomised clinical trials (irrespective of language, blinding, or publication status) comparing liver resection (alone or in combination with radiofrequency ablation or cryoablation) versus other palliative treatments (chemotherapy or hormone-therapy or immunotherapy) or no treatment in patients with liver metastases from neuroendocrine tumours, which cannot be completely resected, were considered for the review.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion.

MAIN RESULTS

We were unable to identify any randomised clinical trial suitable for inclusion in this review.

AUTHORS' CONCLUSIONS

The literature provides no evidence from randomised clinical trials in order to assess the role of cytoreductive surgery in non-resectable liver metastases from gastro-entero-pancreatic neuroendocrine tumours. High-quality randomised clinical trials may become feasible to perform if their conduct and study design is thoroughly considered in all their practical and methodological aspects. Pilot randomised clinical trials, which can guide the study design of definitive randomised clinical trials, are necessary.

Liver metastases of neuroendocrine carcinomas: interventional treatment via transarterial embolization, chemoembolization and thermal ablation

The aim of this review article is to provide a practical clinical guideline for indication, technical aspects, protocol guideline and strategies for the interventional treatment of liver metastases from neuroendocrine tumors and focusing on the results of various protocols of management. The response to therapy, in the published articles, is calculated on the basis of the following clinical parameters; including symptomatic response (SR), biologic response (BR), morphological response (MR), progress free survival (PFS), and survival periods (SP). Transarterial chemoembolization (TACE) has been associated with SR rates of 60-95%, BR of 50-90%, MR of 33-80%, SR of 20-80 months, and a 5-year survival of between 50% and 65%. PFS was also between 18 and 24 months. In the transarterial embolization (TAE) group, SR was similar to the TACE group, MR was 32% and 82%, survival was between 18 and 88 months with a survival rate of 40-67%, and BR was between 50% and 69%. Radiofrequency ablation (RFA), either percutaneous or during surgery, has been associated with SR of 71-95% for a mean duration of 8-10 months, BR of 65%, and mean SP of 1.6 years after ablation. The mean survival following surgical resection for operable cases is 4.26 years+/-S.D.: 1.1.

CONCLUSION

The interventional protocols for the management of liver metastases from neuroendocrine tumors: for oligonodular liver metastatic deposits, local resection or RFA and/or LITT is recommended, while in multinodular diseases with higher tumor load, TACE or TAE is recommended.

Predictors of long-term survival after liver transplantation for metastatic endocrine tumors: an 85-case French multicentric report

Liver transplantation (LTx) for metastatic endocrine tumors (MET) remains controversial due to the lack of clear selection criteria. From 1989 to 2005, 85 patients underwent LTx for MET. The primary tumor was located in the pancreas or duodenum in 40 cases, digestive tract in 26 and bronchial tree in five. In the remaining 14 cases, primary location was undetermined at the time of LTx. Hepatomegaly (explanted liver > or =120% of estimated standard liver volume) was observed in 53 patients (62%). Extrahepatic resection was performed concomitantly with LTx in 34 patients (40%), including upper abdominal exenteration (UAE) in seven. Postoperative in-hospital mortality was 14%. Overall 5-year survival was 47%. Independent factors of poor prognosis according to multivariate analysis included UAE (relative risk (RR): 3.72), primary tumor in duodenum or pancreas (RR: 2.94) and hepatomegaly (RR: 2.63). After exclusion of cases involving concomitant UAE, the other two factors were combined into a risk model. Five-year survival rate was 12% for the 23 patients presenting both unfavorable prognostic factors versus 68% for the 55 patients presenting one or neither factor (p < 10(-7)). LTx can benefit selected patients with nonresectable MET. Patients presenting duodeno-pancreatic MET in association with hepatomegaly are poor indications for LTx.