Neuroendocrine tumors metastatic to the liver: how to select patients for liver transplantation?

A review on management discussions of small intestinal neuroendocrine tumors ‘midgut carcinoids’

European Neuroendocrine Tumor Society staging, together with the Ki67 grading system, has appeared as superior for classification of neuroendocrine tumors (NET). The management of small intestinal NET (SI-NET) has been overall controversial. Mesenteric metastases occur also with the smallest SI-NET, and the majority of patients risk to ultimately progress with liver metastases. 68Gallium (somatostatin receptor)/PET/CT has appeared as most sensitive for imaging, and fluorodeoxyglucose-PET is recommended to identify lesions with high proliferation. Our treatment policy for SI-NET is to initiate somatostatin analog treatment, and in order to prevent abdominal complications we recommend early intestinal resection for removal of primary tumors and clearance of lymph node metastases. Liver metastases are liberally treated by resection (or ablation), as this can efficiently palliate carcinoid syndrome-associated symptoms.

Liver transplantation for malignancies

Liver transplantation (LT) has become an acceptable and effective treatment for selected patients with hepatocellular carcinoma with excellent outcomes. More recently, LT has been tried in different primary and secondary malignancies of the liver. The outcomes of LT for very selected group of patients with hilar cholangiocarcinoma (CCA) have been promising. Excellent results have been reported in LT for patients with unresectable hepatic epithelioid hemangioendothelioma (HEHE). In contrast to excellent results after LT for HEHE, results of LT for angiosarcoma have been disappointing with no long-term survivors. Hepatoblastoma (HB) is the most common primary liver cancer in pediatric age group. Long-term outcomes after LT in patients with unresectable tumor and good response to chemotherapy have been promising. Indication for LT for hepatic metastasis from neuroendocrine tumors (NETs) is mainly for patients with unresectable tumors and for palliation of medically uncontrollable symptoms. Posttransplant survival in those patients with low tumor activity index is excellent, despite recurrence of the tumor. More recent limited outcomes data on LT for unresectable hepatic metastases from colorectal cancer have claimed some survival benefit compared to the previous reports. However, due to the high rate of tumor recurrence in a very short time after LT, especially in the era of organ shortage, this indication has not been favored by the transplant community.

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.

Modified liver-free multivisceral transplantation for a metastatic small bowel neuroendocrine tumor: a case report

Neuroendocrine tumors originating from the small bowel frequently metastasize to the lymph nodes and/or liver. Although surgical extirpation of the primary tumor and locoregional metastases epitomizes the management of patients with such tumors, this is not always possible with conventional surgical techniques. Nonresectable, slow-growing tumors involving the mesenteric root represent a generally accepted indication for deceased donor intestinal and multivisceral transplantation. Furthermore, vascularized sentinel forearm flaps offer opportunities for monitoring graft rejection and tailoring immunosuppression regimens. Here, we report the first documented case of modified liver-free multivisceral transplantation preceded by neoadjuvant 177-lutetium peptide receptor radionuclide therapy in a patient with a small bowel neuroendocrine tumor and extensive lymph node metastases in the mesenterium. At a follow-up of 21 months the patient is biochemically and radiologically disease-free.

Liver transplantation for neuroendocrine tumour liver metastases

OBJECTIVE

Search and review of available literature were made to define the indications for and timing of liver transplantation for neuroendocrine tumour (NET) liver metastases.

METHODS

Electronic bibliographical databases were searched. Prospective and retrospective cohort studies and case-controlled studies were used for qualitative and quantitative synthesis of the systematic review. Reports of patients with liver transplantation alone for NET liver metastases of any origin or combined with resection of extrahepatic tumour deposits were recruited.

RESULTS

The number of patients who have undergone liver transplantation for NET liver metastases is 706. The post-transplant 5-year survival rate from the time of diagnosis was approximately 70%. NET patients with metastases confined to the liver and not poorly differentiated are favourable candidates for liver transplantation. Selection of patients based on evolution of tumours over 6 months is not recommended.

CONCLUSION

Non-resectable NET liver metastasis resistant to medical treatment and confined to the liver is an accepted indication for liver transplantation.

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.

Update on pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (pNETs) are relatively rare tumors comprising 1-2% of all pancreas neoplasms. In the last 10 years our understanding of this disease has increased dramatically allowing for advancements in the treatment of pNETs. Surgical excision remains the primary therapy for localized tumors and only potential for cure. New surgical techniques using laparoscopic approaches to complex pancreatic resections are a major advancement in surgical therapy and increasingly possible. With early detection being less common, most patients present with metastatic disease. Management of these patients requires multidisciplinary care combining the best of surgery, chemotherapy and other targeted therapies. In addition to surgical advances, recently, there have been significant advances in systemic therapy and targeted molecular therapy.

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.

Indication for liver transplantation in young patients with small intestinal NETs is rare?

BACKGROUND

A majority of patients with small intestinal neuroendocrine tumors (SI-NETs) present with or develop liver metastases (LM). A number of treatments for LM are used clinically, including liver transplantation (LTx). Indications for LTx are under debate; young age(<65 years), absence of extrahepatic disease, resected primary tumor and limited extent of LM have been suggested as inclusion criteria for LTx with the aim to optimize outcome.

MATERIALS AND METHODS

From our series of 672 patients with SI-NET treated at the University Hospital in Uppsala between 1985 and 2012, we identified 78 patients according to the following criteria: <65 years of age, locoregional surgery (LRS) of the primary tumor and mesenteric metastases successfully performed, LM present but no extrahepatic disease. Baseline was chosen as the first date the following points were met: First visit to our center,LRS performed, LM present. The patients underwent treatment according to the standard clinical protocols at our center, and during this time period we did not perform or refer any SI-NET patients for LTx. Kaplan-Meier survival analyses were performed in three different groups based on hypothetical criteria for LTx.

RESULTS

Five-year overall survival rates for patients <65 years (n = 78) and <55 years (n = 36) of age were 84 ± 8 and 92 ± 9 %, respectively. For patients fulfilling the Milan criteria (n = 33) the 5-year survival was 97 ± 6 %.

CONCLUSIONS

Most young patients (<65 years) with SINET and LM have a favorable survival with standardized multimodality treatment. Indeed, most survival figures reported after LTx of NET do not surpass these figures.

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.

Therapy for metastatic pancreatic neuroendocrine tumors

BACKGROUND

Pancreatic neuroendocrine tumors (pNETs) are frequently malignant (50-80%, except for insulinoma) and may show an aggressive course with metastases to the liver as well as more distant sites. These heterogeneous neoplasms include functioning tumors, which secrete a variety of peptide hormones, and non-functioning tumors (up to 90% of pNETs), which often show metastases at the time of diagnosis.

METHODS

A PubMed search was performed for English-language publications from 1995 through December 2012. Reference lists from studies selected were manually searched to identify further relevant reports. Manuscripts comparing different therapeutic options and advances for metastatic pNETs were selected.

RESULTS

The therapeutic options for metastatic pNETs are expanding and include surgery, which remains the only curative approach, liver-directed therapies, and medical therapy. In selected cases also liver transplantation (OLT) may be considered. The option of OLT for metastatic disease is unique to neuroendocrine tumors. Recently, novel promising targeted therapies have been proposed for progressive well-differentiated pNETs.

CONCLUSIONS

The best therapeutic approach for pNETs is still matter of debating. However, since pNETs often show a more indolent behavior compared to other malignancies, the preservation of the quality of life of the patient and the personalization of the therapy according to tumor's and patient's features are mandatory.

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.

A tale of two tumors: treating pancreatic and extrapancreatic neuroendocrine tumors

Despite their perceived rarity, gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rising in incidence and prevalence. The biology, natural history, and therapeutic options for GEP-NETs are heterogeneous: NETs arising in the pancreas can be distinguished from those arising elsewhere in the gastrointestinal tract, and therapy is dichotomized between these two groups. Somatostatin analogues are the mainstay of oncologic management of bowel NETs; everolimus, streptozocin, and sunitinib are approved to treat pancreatic NETs. There are significant differences in molecular genetics between pancreatic and extrapancreatic NETs, and studies are evaluating whether additional NET patients may benefit from targeted agents. We discuss the distinguishing features of these two groups of tumors, as well as the therapeutic implications of the distinction. We also examine the evolving therapeutic landscape and discuss the likelihood that treatment will be developed independently for pancreatic and extrapancreatic gastrointestinal NETs, with novel therapeutics effective for newly identified pathologically or molecularly defined subgroups.

Update on surgical treatment of pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms (PNENs) are rare and account for only 2%-4% of all pancreatic neoplasms. All PNENs are potential (neurendocrine tumors PNETs) or overt (neuroendocrine carcinomas PNECs) malignant, but a subset of PNETs is low-risk. Even in case of low-risk PNETs surgical resection is frequently required to treat hormone-related symptoms and to obtain an appropriate pathological diagnosis. Low-risk PNETs in the body and the tail are ideal for minimally-invasive approaches which should be tailored to the individual patient. Generally, surgeons must aim for parenchyma sparing in these cases. In high-risk and malignant PNENs, indications for tumor resection are much wider than for pancreatic adenocarcinoma, in many cases due to the relatively benign tumor biology. Thus, patients with locally advanced and metastatic PNETs may benefit from extensive resection. In experienced hands, even multi-organ resections are accomplished with acceptable perioperative morbidity and mortality rates and are associated with excellent long term survival. However, poorly differentiated neoplasms with high proliferation rates are associated with a dismal prognosis and may frequently only be treated with chemotherapy. The evidence on surgical treatment of PNENs stems from reviews of mostly single-center series and some analyses of nation-wide tumor registries. No randomized trial has been performed to compare surgical and non-surgical therapies in potentially resectable PNEN. Though such a trial would principally be desirable, ethical considerations and the heterogeneity of PNENs preclude realization of such a study. In the current review, we summarize recent advances in the surgical treatment of PNENs.

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.

Current challenges in liver transplantation for hepatocellular carcinoma

Liver transplantation (LT) is the best option of cure for hepatocellular carcinoma (HCC). Notwithstanding several alternatives, Milan Criteria remain the cornerstone for patient selection. Currently, expanded criteria patients are unsuitable for LT without taking downstaging approaches and response to therapies into consideration. Relative weight of HCC as indication to LT is increasing and that generates competition with MELD-described non-cancer indications. Allocation policies should be adjusted accordingly, considering principles of urgency and utility in the management of the waiting list and including transplant benefit to craft equitable criteria to deal with the limited resource of donated grafts. Maximization of cost-effectiveness of LT in HCC can be also pursued through changes in immunosuppression policies and multimodal management of post-transplant recurrences. This review is focused on those constantly mutating challenges that have to be faced by anyone dealing with the management of HCC in the context of liver transplantation.

Pancreatic neuroendocrine tumor accompanied with multiple liver metastases

Pancreatic neuroendocrine tumor (P-NET) is rare and slow-growing. Current classifications predict its prognosis and postoperative recurrence. Curative resection is ideal, although often difficult, because over 80% of patients have unresectable multiple liver metastases and extrahepatic metastasis. Aggressive surgery for liver metastases is important to improve survival. Aggressive or cytoreductive surgery for liver metastases is indicated to reduce hormone levels and improve symptoms and prognosis. Liver transplantation was originally conceived as an ideal therapy for unresectable liver metastases. Unfortunately, there is no clear consensus on the role and timing of surgery for primary tumor and liver metastases. Surgeons still face questions in deciding the best surgical scenario in patients with P-NET with unresectable liver metastases.

Hepatic radioembolization as a bridge to liver surgery

Treatment of oncologic disease has improved significantly in the last decades and in the future a vast majority of cancer types will continue to increase worldwide. As a result, many patients are confronted with primary liver cancers or metastatic liver disease. Surgery in liver malignancies has steeply improved and curative resections are applicable in wider settings, leading to a prolonged survival. Simultaneously, radiofrequency ablation (RFA) and liver transplantation (LTx) have been applied more commonly in oncologic settings with improving results. To minimize adverse events in treatments of liver malignancies, locoregional minimal invasive treatments have made their appearance in this field, in which radioembolization (RE) has shown promising results in recent years with few adverse events and high response rates. We discuss several other applications of RE for oncologic patients, other than its use in the palliative setting, whether or not combined with other treatments. This review is focused on the role of RE in acquiring patient eligibility for radical treatments, like surgery, RFA, and LTx. Inducing significant tumor reduction can downstage patients for resection or, through attaining stable disease, patients can stay on the LTx waiting list. Hereby, RE could make a difference between curative of palliative intent in oncologic patient management. Prior to surgery, the future remnant liver volume might be inadequate in some patients. In these patients, forming an adequate liver reserve through RE leads to prolonged survival without risking post-operative liver failure and minimizing tumor progression while inducing hypertrophy. In order to optimize results, developments in procedures surrounding RE are equally important. Predicting the remaining liver function after radical treatment and finding the right balance between maximum tumor irradiation and minimizing the chance of inducing radiation-related complications are still challenges.

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.

Liver transplantation for metastatic liver malignancies

PURPOSE OF REVIEW

Liver transplantation is a validated treatment of primary hepatobiliary tumours. Over the last decade, a renewed interest for liver transplantation as a curative treatment of colorectal liver metastasis (CR-LM) and neuro-endocrine metastasis (NET-LM) has developed.

RECENT FINDINGS

The ELTR and UNOS analyses showed that liver transplantation may offer excellent disease-free survival (ranging from 30 to 77%) in case of NET-LM, on the condition that stringent selection criteria are implemented. The interest for liver transplantation in the treatment of CR-LM has been fostered by the Norwegian SECA study. Five-year A 5-year survival rate of 60% could be reached. Despite the high recurrence rate (90%), one-third of patients were disease free following pulmonary surgery for metastases.

SUMMARY

Liver transplantation will take a more prominent place in the therapeutic algorithm of CR-LM and NET-LM. Larger experiences are necessary to improve knowledge about tumour biology and to refine selection criteria. A multimodal approach adding neo and adjuvant medical treatment to the transplant procedure will be key to bring this oncologic transplant project into the clinical arena. The preserved liver function in these patients will allow a more deliberate access to split liver and living donation for these indications.

Current status of the organ replacement approach for malignancies and an overture for organ bioengineering and regenerative medicine

Significant achievements in the organ replacement approach for malignancies over the last 2 decades opened new horizons, and the age of "Transplant Oncology" has dawned. The indications of liver transplantation for malignancies have been carefully expanded by a strict patient selection to assure comparable outcomes with non-malignant diseases. Currently, the Milan criteria, gold standard for hepatocellular carcinoma, are being challenged by high-volume centers worldwide. Neoadjuvant chemoradiation therapy and liver transplantation for unresectable hilar cholangiocarcinoma has been successful in specialized institutions. For other primary and metastatic liver tumors, clinical evidence to establish standardized criteria is lacking. Intestinal and multivisceral transplantation is an option for low-grade neoplasms deemed unresectable by conventional surgery. However, the procedure itself is in the adolescent stage. Solid organ transplantation for malignancies inevitably suffers from "triple distress," i.e., oncological, immunological, and technical. Organ bioengineering and regenerative medicine should serve as the "triple threat" therapy and revolutionize "Transplant Oncology."

Liver transplantation for hepatic tumors: A systematic review

Improvements in the medical and pharmacological management of liver transplantation (LT) recipients have led to a better long-term outcome and extension of the indications for this procedure. Liver tumors are relevant to LT; however, the use of LT to treat malignancies remains a debated issue because the high risk of recurrence. In this review we considered LT for hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), liver metastases (LM) and other rare tumors. We reviewed the literature, focusing on the past 10 years. The highly selected Milan criteria of LT for HCC (single nodule < 5 cm or up to 3 nodules < 3 cm) have been recently extended by a group from the University of S. Francisco (1 lesion < 6.5 cm or up to 3 lesions < 4.5 cm) with satisfying results in terms of recurrence-free survival and the “up-to-seven criteria”. Moreover, using these criteria, other transplant groups have recently developed downstaging protocols, including surgical or loco-regional treatments of HCC, which have increased the post-operative survival of recipients. CCA may be treated by LT in patients who cannot undergo liver resection because of underlying liver disease or for anatomical technical challenges. A well-defined protocol of chemoirradiation and staging laparotomy before LT has been developed by the Mayo Clinic, which has resulted in long term disease-free survival comparable to other indications. LT for LM has also been investigated by multicenter studies. It offers a real benefit for metastases from neuroendocrine tumors that are well differentiated and when a major extrahepatic resection is not required. If LT is an option in these selected cases, liver metastases from colorectal cancer is still a borderline indication because data concerning the disease-free survival are still lacking. Hepatoblastoma and hemangioendothelioma represent rare primary tumors for which LT is often the only possible and effective cure because of the frequent multifocal, intrahepatic nature of the disease. LT is a very promising procedure for both primary and secondary liver malignancies; however, it needs an accurate evaluation of the costs and benefits for each indication to balance the chances of cure with actual organ availability.

Liver transplantation for malignancy: Current treatment strategies and future perspectives

In 1967, Starzl et al performed the first successful liver transplantation for a patient diagnosed with hepatoblastoma. In the following, liver transplantation was considered ideal for complete tumor resection and potential cure from primary hepatic malignancies. Several reports of liver transplantation for primary and metastatic liver cancer however showed disappointing results and the strategy was soon dismissed. In 1996, Mazzaferro et al introduced the Milan criteria, offering liver transplantation to patients diagnosed with limited hepatocellular carcinoma. Since then, liver transplantation for malignant disease is an ongoing subject of preclinical and clinical research. In this context, several aspects must be considered: (1) Given the shortage of deceased-donor organs, long-term overall and disease free survival should be comparable with results obtained in patients transplanted for non-malignant disease; (2) In this regard, living-donor liver transplantation may in selected patients help to solve the ethical dilemma of optimal individual patient treatment vs organ allocation justice; and (3) Ongoing research focusing on perioperative therapy and anti-proliferative immunosuppressive regimens may further reduce tumor recurrence in patients transplanted for malignant disease and thus improve overall survival. The present review gives an overview of current indications and future perspectives of liver transplantation for malignant disease.

Liver transplantation for unresectable neuroendocrine tumor liver metastases

BACKGROUND

Liver transplantation (LT) is performed in selected patients with neuroendocrine hepatic metastases. Survival benefit and the risk of tumor recurrence after LT, also exacerbated by immunosuppressive therapy, remain important clinical issues. Whether patients with particular types of neuroendocrine tumors (NET) benefit more than others is unclear.

METHODS

Bibliographical searches were performed in PubMed for the terms "liver transplantation and neuroendocrine tumors," "liver transplant and neuroendocrine tumors," "liver transplantation and immunosuppressive therapy," "tumor recurrence."

RESULTS

Promising results have been reported for LT for NET metastases with 5-year survival of up to 90 % in patients with well-differentiated gastroenteropancreatic NETs, but only few patients are free of tumor 5 years after LT. Better outcomes have been reported for gastrointestinal tumors than for pancreatic NETs for both survival and risk or recurrence after LT. Selection criteria for LT are limited and include the 2007 Milan Criteria and the 2012 European Neuroendocrine Tumor Society guidelines, including: well-differentiated NET (Ki-67 <10 %), age <55 years, absence of extrahepatic disease, primary tumor removed before transplantation, stable disease for at least 6 months before LT, and <50 % liver involvement.

CONCLUSIONS

LT might be considered in carefully selected patients. The risk of tumor recurrence remains a significant clinical problem after LT, but data focused on immunosuppression issue are lacking, and there are no currently approved strategies for prevention of recurrence or follow-up protocols. Further studies are needed to define universally accepted inclusion criteria, reliable predictors of better outcome, and optimal timing for LT.

Transplantation and surgical strategies in patients with neuroendocrine liver metastases: protocol of four systematic reviews

Background

Hepatic metastases of neuroendocrine tumors (NETs) are considered a major prognostic factor associated with significantly reduced survival compared to patients without liver metastases. Several surgical and nonsurgical strategies are present to treat resectable and nonresectable liver metastases, some of which have the potential to cure liver mestatases.

Objective

The aims of the four systematic reviews presented in the paper are to determine the effectiveness of liver resection versus nonsurgical treatment of patients with NET liver metastases, to investigate the impact of neoadjuvant and adjuvant treatment options on the tumor-free survival, to assess the role of liver transplantation in patients presenting with unresectable bilateral hepatic metastases, and to evaluate the role of primary tumor resection in presence of unresectable liver metastases.

Methods

Literature search was performed on Medical Literature Analysis and Retrieval System Online, Excerpta Medica Database, and the Cochrane Library (Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, and Cochrane Central Register of Controlled Trials). No language restrictions were applied. Randomized controlled trials, prospective and retrospective comparative cohort studies, and case-control studies will be used for the qualitative and quantitative synthesis of the systematic reviews. Case series will be only included in a separate database for descriptive purposes.

Results

This study is ongoing and presents a protocol system of four systematic reviews that will assist in determining the effectiveness of liver resection versus nonsurgical treatment of patients with NET liver metastases. This study is also assumed to investigate the impact of neoadjuvant and adjuvant treatment options on the tumor-free survival, the role of liver transplantation, and the relevance of primary tumor resection in presence of unresectable liver metastasis.

Conclusions

The systematic reviews will show the current evidence based on the effectiveness of surgical strategies in patients with NET liver metastases and serve as basis for clinical practice guidelines.

Trial Registration

The systematic reviews have been prospectively registered with the International Prospective Register of Systematic Reviews: liver resection (CRD42012002652); http://www.crd.york.ac.uk/prospero/display_record.asp?ID=CRD42012002652 (Archived by WebCite at http://www.webcitation.org/6LQUqMnqL,). neoadjuvant and adjuvant treatment strategies (CRD42012002656); http://www.crd.york.ac.uk/prospero/display_record.asp?ID=CRD42012002656 (Archived by WebCite at http://www.webcitation.org/6LQVvEHuf). liver transplantation (CRD42012002655); http://www.crd.york.ac.uk/prospero/display_record.asp?ID=CRD42012002655 (Archived by WebCite at http://www.webcitation.org/6LQW7WFo3,). resection of the locoregional primary NET (CRD42012002654); http://www.crd.york.ac.uk/prospero/display_record.asp?ID=CRD42012002654 (Archived by WebCite at http://www.webcitation.org/6LQWEIuGe).

Outcome after resection and radiofrequency ablation of liver metastases from small intestinal neuroendocrine tumours

BACKGROUND

In patients with small intestinal neuroendocrine tumour (SI-NET), liver resection or radiofrequency ablation (RFA) of liver metastases is performed for palliation of carcinoid syndrome, and in an effort to improve survival. Data are generally reported from case series, and no randomized trials have studied these treatments. The aim was to compare outcome after liver resection and/or RFA with that of non-surgical treatment in patients with liver metastases from SI-NET.

METHODS

The study included patients with liver metastases from SI-NET who underwent liver RFA/resection or were treated non-surgically. A propensity score match was performed to reduce bias between groups, using baseline variables such as the Charlson co-morbidity index, age, symptoms, carcinoid heart disease, extent of metastases and proliferation index.

RESULTS

Some 103 patients who had RFA and/or liver resection were compared with 273 controls. Propensity score matching resulted in two matched groups, each of 72 patients, with no significant differences in baseline variables. The matched resection/RFA and control groups showed no difference in overall survival (both 74 per cent at 5 years; P = 0·869) or disease-specific survival (74 versus 78 per cent respectively at 5 years; P = 1·000). However, urinary 5-hydroxyindoleacetic acid levels were lower (median 77 versus 120 µmol per 24 h; P = 0·005) and the proportion of patients with progressive disease within the liver was smaller (2 of 18 versus 8 of 18; P < 0·001) in the resection/RFA group after 5 years.

CONCLUSION

These data do not support the use of liver resection and/or RFA in an effort to prolong survival in patients with liver metastases from SI-NET.

Management of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors account for 1% to 2% of pancreatic neoplasms and may occur sporadically or as part of a hereditary syndrome. Patients may present with symptoms related to hormone secretion by functional tumors or to locally advanced or metastatic nonfunctional tumors. Asymptomatic pancreatic neuroendocrine tumors are increasingly detected incidentally during abdominal imaging performed for other reasons. The management of localized pancreatic neuroendocrine tumors is surgical resection. Hepatic metastases are common and their management involves a variety of liver-directed therapies, which should be tailored according to extent of disease, symptoms, presence of extrahepatic metastases, and patient performance status.

Gastroenteropancreatic neuroendocrine tumors: role of imaging in diagnosis and management

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of neoplasms that arise from cells of the diffuse neuroendocrine system and are characterized by a wide spectrum of clinical manifestations. All NETs are potentially malignant but differ in their biologic characteristics and the probability of metastatic disease. The pathologic classification of these tumors relies on their proliferation and differentiation. In the past decades, several nomenclatures have been proposed to stratify neuroendocrine tumors, but the World Health Organization classification is the one that is most widely accepted and used. The diagnosis of neuroendocrine tumor relies on clinical manifestation, laboratory parameters, imaging features, and tissue biomarkers in a biopsy specimen. With improved understanding of the natural history and lesion biology, management of GEP-NETs has also evolved. Although surgery remains the only potentially curative therapy for patients with primary GEP-NETs, other available treatments include chemotherapy, interferon, somatostatin analogs, and targeted therapies. Recent improvements in both morphologic and functional imaging methods have contributed immensely to patient care. Morphologic imaging with contrast agent-enhanced multidetector computed tomography and magnetic resonance imaging is most widely used for initial evaluation and staging of disease in these patients, whereas functional imaging techniques are useful both for detection and prognostic evaluation and can change treatment planning.

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 of liver metastases in patients with digestive neuroendocrine tumors

BACKGROUND

Liver metastases are a strong prognostic indicator in patients with gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs). Therapeutic options for metastatic NETs are expanding and not mutually exclusive.

AIMS

This paper reviews the literature relating to multidisciplinary approach towards GEP-NET metastases, to highlight advances in knowledge regarding these tumors, and to understand the interdisciplinary management of individual patients.

METHODS

A PubMed search was performed for English-language publications from 1995 through 2012. Reference lists from studies selected were manually searched to identify further relevant reports. Manuscripts comparing different therapeutic options and advances for GEP-NET-related liver metastases were selected.

RESULTS

There is considerable controversy regarding the optimal management of GEP-NET metastases. Although radical surgery still remains the gold standard, a variety of other therapeutic options are available for metastatic GEP-NETs, including loco-regional chemotherapy/radiotherapy, radioembolization, systemic peptide receptor radionuclide therapy, biotherapy, and chemotherapy. In selected patients, liver transplantation should also be considered. Systemic somatostatin analogues and/or interferon show anti-proliferative effects, representing an appropriate first-line treatment for most patients. In advanced metastatic NETs, recent options include targeted therapies (i.e., everolimus and sunitinib).

CONCLUSIONS

It is evident that multidisciplinary care and multimodality treatments remain the cornerstone of management of NET patients. Since NETs often show a more indolent behavior compared to other malignancies, physicians should aim to preserve a satisfactory quality of life for the patient by personalizing the therapeutic approach according to the tumor's features and prognostic factors.

Neuroendocrine tumor disease: an evolving landscape

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) represent a heterogenous group of tumors arising from a variety of neuroendocrine cell types. The incidence and prevalence of GEP-NENs have markedly increased over the last three decades. Symptoms are often absent in early disease, or vague and nonspecific even in advanced disease. Delayed diagnosis is thus common. Chromogranin A is the most commonly used biomarker but has limitations as does the proliferative marker Ki-67%, which is often used for tumor grading and determination of therapy. The development of a multidimensional prognostic nomogram may be valuable in predicting tumor behavior and guiding therapy but requires validation. Identification of NENs that express somatostatin receptors (SSTR) allows for SSTR scintigraphy and positron emission tomography imaging using novel radiolabeled compounds. Complete surgical resection of limited disease or endoscopic ablation of small lesions localized in stomach or rectum can provide cure; however, the majority of GEP-NENs are metastatic (most frequently the liver and/or mesenteric lymph nodes) at diagnosis. Selected patients with metastatic disease may benefit from advanced surgical techniques including hepatic resection or liver transplantation. Somatostatin analogs are effective for symptomatic treatment and exhibit some degree of antiproliferative activity in small intestinal NENs. There is a place for streptozotocin, temozolomide, and capecitabine in the management of pancreatic NENs, while new agents targeting either mTOR (everolimus) or angiogenic (sunitinib) pathways have shown efficacy in these lesions.

Surgical treatment of liver metastases in neuroendocrine neoplasms

Neuroendocrine neoplasms (NENs) are a distinctive entity, and nearly 10% of patients already have liver metastases at presentation. The management of neuroendocrine liver metastases (NEN-LM) is complex with differing patterns of metastatic presentation. An aggressive approach should be used to resect the primary tumor, to remove regional lymph nodes, and to resect or treat appropriate distant metastases (including liver tumors). Despite having an indolent course, NENs have a significantly reduced survival when liver metastases are untreated. Though a wide range of therapies are now available with a multimodal approach to the treatment, surgical treatment offers the only chance for a significant survival prolongation and/or improvement of symptoms and quality of life. A review of the existing surgical modalities for NEN-LM is discussed in this paper.

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.

A multimodal approach to the management of neuroendocrine tumour liver metastases

Neuroendocrine tumours (NETs) are often indolent malignancies that commonly present with metastatic disease in the liver. Surgical, locoregional, and systemic treatment modalities are reviewed. A multidisciplinary approach to patient care is suggested to ensure all therapeutic options explored.

Model for end-stage liver disease exceptions in the context of the French model for end-stage liver disease score-based liver allocation system

Model for End-Stage Liver Disease (MELD) score-based allocation systems have been adopted by most countries in Europe and North America. Indeed, the MELD score is a robust marker of early mortality for patients with cirrhosis. Except for extreme values, high pretransplant MELD scores do not significantly affect posttransplant survival. The MELD score can be used to optimize the allocation of allografts according to a sickest first policy. Most often, patients with small hepatocellular carcinomas (HCCs) and low MELD scores receive extra points, which allow them appropriate access to transplantation comparable to the access of patients with advanced cirrhosis and high MELD scores. In addition to patients with advanced cirrhosis and HCC, patients with a number of relatively uncommon conditions have low MELD scores and a poor prognosis in the short term without transplantation but derive excellent benefits from transplantation. These conditions, which correspond to the so-called MELD score exceptions, justify the allocation of a specific score for appropriate access to transplantation. Here we report the conclusions of the French consensus meeting. The goals of this meeting were (1) to identify which conditions merit MELD score exceptions, (2) to list the criteria needed for defining each of these conditions, and (3) to define a reasonable time interval for organ allocation for each MELD exception in the general context of organ shortages. MELD exceptions were discussed in an attempt to reconcile the concepts of transparency, equity, justice, and utility.

Liver transplantation for hepatic metastases of neuroendocrine pancreatic tumors: a survival-based analysis

BACKGROUND

Liver transplantation (LT) has been accepted as a treatment in selected cases of neuroendocrine tumors (NETs) with hepatic metastases.

PATIENTS AND METHODS

A systematic review of the literature was conducted to evaluate long-term patient survival in the instances of LT for pancreatic NET. Univariate and multivariate regression analyses and survival analysis were performed.

RESULTS

Fifty-three clinical studies were screened. Data from 20 studies encompassing 89 transplanted patients were included in the study. Most primary tumors were endocrine pancreatic tumors (n=69), with gastrinomas representing the most frequent diagnosis (n=21). There were 61 functioning pancreatic NET. Simultaneous LT and pancreatic NET resections were performed in 45 instances. Cumulative 1-, 3-, and 5-year survival was 71%, 55%, and 44%, respectively, with a calculated mean survival of 54.45±6.31 months. Vasoactive intestinal peptide (VIPomas) had the best overall survival. Recurrence-free survival at 1, 3, and 5 years was 84%, 47%, and 47%, respectively. Recipient age more than or equal to 55 years (P=0.0242) and simultaneous LT-pancreatic resection (P=0.0132) were found to be significant predictors of worse survival by both univariate and multivariate Cox proportional hazard analyses. A scoring system was developed, with prognostic points assigned as follows: age more than or equal to 55 years:age less than 55 years=1:0 points and simultaneous LT-pancreatic resection:LT alone=1:0 points. This stratification delineated three separate population samples corresponding to patients with scores of 0, 1, and 2, respectively. The calculated 5-year survival for scores 0, 1, and 2 was 61%, 40%, and 0%, respectively (P=0.0023).

CONCLUSIONS

Despite the limitations of this retrospective analysis, good results can be achieved even for pancreatic NET primaries if the above-proposed scoring system is applied.

Surgery for gastroenteropancreatic neuroendocrine tumors (GEPNETS)

The only therapy with the potential for complete cure of patients with gastroenteropancreatic neuroendocrine tumors is complete surgical excision. Surgical options per se are often dictated by the tumor's site of origin, degree of tumor burden, and overall health or debility of the individual patient. This article considers different options based on the type of tumor and site of origin.

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.

Multimodal management of neuroendocrine liver metastases

BACKGROUND

The incidence of neuroendocrine tumours (NET) has increased over the past three decades. Hepatic metastases which occur in up to 75% of NET patients significantly worsen their prognosis. New imaging techniques with increasing sensitivity enabling tumour detection at an early stage have been developed. The treatment encompasses a panel of surgical and non-surgical modalities.

METHODS

This article reviews the published literature related to management of hepatic neuroendocrine metastases.

RESULTS

Abdominal computer tomography, magnetic resonance tomography and somatostatin receptor scintigraphy are widely accepted imaging modalities. Hepatic resection is the only potentially curative treatment. Liver transplantation is justified in highly selected patients. Liver-directed interventional techniques and locally ablative measures offer effective palliation. Promising novel therapeutic options offering targeted approaches are under evaluation.

CONCLUSIONS

The treatment of neuroendocrine liver metastases still needs to be standardized. Management in centres of expertise should be strongly encouraged in order to enable a multidisciplinary approach and personalized treatment. Development of molecular prognostic factors to select treatment according to patient risk should be attempted.

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.