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

Liver transplantation and multivisceral transplantation in the management of patients with advanced neuroendocrine tumours

Orthotopic liver transplantation (OLT) represents a generally accepted albeit somewhat controversially discussed therapeutic strategy in highly selected patients with non-resectable hepatic metastases from neuroendocrine tumours (NET). Whilst there are some exclusion criteria, these are not universally followed, and the optimal set of inclusion parameters for deeming patients eligible has not yet been elucidated. This is due to heterogeneity in the study populations, as well differing approaches employed and also divergences in selection criteria between centres. Recent data have suggested that OLT may represent the most efficacious approach in terms of overall and disease-free survival to the management of NET metastatic to the liver when conducted in accordance with the modified Milan criteria. Therefore, a consensus set of selection criteria requires definition to facilitate stringent and fair allocation of deceased-donor organs, as well as consideration for living-donor organs. In the context of classically non-resectable metastatic tumour bulk, multivisceral transplantation with or without the liver may also be indicated, yet experience is very limited. In this review, we discuss the diagnostic work-up of patients in whom the aforementioned transplantation approaches are being considered, critically analyse the published experience and also anticipate future developments in this field, including a discussion of immediate and longer-term research priorities.

Recurrence of Pancreatic Neuroendocrine Tumors and Survival Predicted by Ki67

Background

Despite evidence of different malignant potentials, postoperative follow-up assessment is similar for G1 and G2 pancreatic neuroendocrine tumors (panNETs) and adjuvant treatment currently is not indicated. This study investigated the role of Ki67 with regard to recurrence and survival after curative resection of panNET.

Methods

Patients with resected non-functioning panNET diagnosed between 1992 and 2016 from three institutions were retrospectively analyzed. Patients who had G1 or G2 tumor without distant metastases or hereditary syndromes were included in the study. The patients were re-categorized into Ki67 0–5 and Ki67 6–20%. Cox regression analysis with log-rank testing for recurrence and survival was performed.

Results

The study enrolled 241 patients (86%) with Ki67 0–5% and 39 patients (14%) with Ki67 6–20%. Recurrence was seen in 34 patients (14%) with Ki67 0–5% after a median period of 34 months and in 16 patients (41%) with Ki67 6–20% after a median period of 16 months (p < 0.001). The 5-year recurrence-free and 10-year disease-specific survival periods were respectively 90 and 91% for Ki67 0–5% and respectively 55 and 26% for Ki67 6–20% (p < 0.001). The overall survival period after recurrence was 44.9 months, which was comparable between the two groups (p = 0.283). In addition to a Ki67 rate higher than 5%, tumor larger than 4 cm and lymph node metastases were independently associated with recurrence.

Conclusions

Patients at high risk for recurrence after curative resection of G1 or G2 panNET can be identified by a Ki67 rate higher than 5%. These patients should be more closely monitored postoperatively to detect recurrence early and might benefit from adjuvant treatment. A clear postoperative follow-up regimen is proposed.

Combined associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) followed by left trisectionectomy and Whipple operation for PNET

Pancreatic neuroendocrine tumor (PNET) is slow-growing, and account only for 2% of all pancreatic primary tumors. Surgical resection is still the only curative treatment for PNET patients. Unfortunately, most of PNETs was found with unresectable multiple liver metastases and extrahepatic metastasis as their characteristics of non-functional and asymptomatic. With advances in liver surgery in these years, especially combined associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), provide a new curative surgical treatment for PNET with liver metastases patient. Here we report a PNET with multiple liver metastases case underwent ALPPS (followed by left trisectionectomy) and Whipple operation within one-stage.

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.

Liver transplantation for unresectable pancreatic neuroendocrine tumors with liver metastases in an era of transplant oncology

Patients with pancreatic neuroendocrine tumors (pNETs) very often present with a metastatic disease at the first diagnosis. Liver transplantation (LT) for unresectable pNET with liver metastases (pNETLM) has been described to prolong survival in highly selected patients, although outcomes were worse than those of patients who underwent LT for gastrointestinal NETLM (GI-NETLM). In this review, several proposed criteria are described with their rationale and controversies. Most of the data used to establish these criteria do not reflect the recent improvements of non-surgical treatments that has changed the landscape of treatment for pNETs, including the development of peptide receptor radionuclide therapy and molecular-targeted agents (sunitinib and everolimus). Properly designed studies are necessary to define the role of down-staging and bridging therapy prior to LT incorporating systemic chemotherapy using these molecular-targeted agents. Also, given the indolent nature of low or intermediate grade pNETs, the best endpoint to compare the efficacy of each treatment option for patients with pNETLM has yet to be determined. Lastly, the definition of "unresectable" remains ambiguous. The indication of the conventional technique of two-staged liver resection with portal vein embolization or the new technique of associating liver partition and portal vein ligation for staged hepatectomy to expand the resectability of wide-spread metastatic liver tumors has been controversial. In an era of transplant oncology, LT should be the last resort for patients who are considered unresectable and otherwise untreatable after an exhaustive multidisciplinary team discussion by all experts in the field. In conclusion, although its long-term outcomes have been promising, the role of LT for unresectable pNETLM as a curative or palliative treatment remains unclear. A well-designed randomized control study is required to elucidate the clinical impact of LT for pNETLM.

The Potential Role of Liver Transplantation as a Treatment Option in Colorectal Liver Metastases

Liver resection is the only potentially curative treatment option in patients with liver metastases from colorectal cancer, but only about 20% of the patients are resectable. Liver transplantation of patients with unresectable liver metastases was attempted in the early era but it was abandoned due to poor survival. During the last decade, several case reports, a controlled pilot study, and a retrospective cohort study indicated that prolonged disease-free survival and overall survival can be obtained in a proportion of these patients. Strict selection criteria have not yet been well defined, but tumor load, response to chemotherapy, pretransplant carcinoembryonic antigen level, and time interval from resection of the primary tumor to transplant are all factors related to outcome. Carefully selected patients may obtain 5-year overall survival that approaches conventional indications for liver transplant. The scarcity of liver grafts is a significant problem, but this can possibly to some extent be addressed by use of extended criteria grafts and novel surgical techniques. There is an increasing interest in liver transplantation in these patients in the transplant community, and currently 4 clinical trials are active and are recruiting.

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.

Update in the Therapy of Advanced Neuroendocrine Tumors

OPINION STATEMENT

Neuroendocrine tumors (NETs) are rare neoplasms, with an estimated annual incidence of ~ 6.9/100,000. NETs arise throughout the body from cells of the diffuse endocrine system. More than half originate from endocrine cells of the gastrointestinal tract and the pancreas, thus being referred to as gastroenteropancreatic NETs (GEP-NETs). The only treatment that offers a cure is surgery; however, most patients are diagnosed with metastatic disease, and curative surgery is usually not an option. These patients can be offered long-term systemic treatment, for both symptomatic relief and tumor growth suppression. Evidence-based treatment options include somatostatin analogs, everolimus (a mTOR inhibitor), sunitinib (a tyrosine kinase inhibitor), and peptide receptor radionuclide therapy, alone or combined with cytoreductive procedures (surgery or liver-directed procedures). Other treatment options being investigated are immunotherapy and epigenetic assessment that may lead to more personalized interventions. We believe that each patient should be thoroughly evaluated and their case discussed by a multidisciplinary team that is up-to-date with all treatment modalities including ongoing clinical trials, before selecting the proper treatment option.

Liver Transplant for Nonhepatocellular Carcinoma Malignancy

Liver transplant is now an acceptable and effective treatment for specific nonhepatocellular malignancies. Worldwide, hilar cholangiocarcinoma accounts for 3% of all primary gastrointestinal malignancies and for 10% of primary hepatobiliary malignancies. For patients who have early-stage, unresectable cholangiocarcinoma, liver transplant preceded by neoadjuvant radiotherapy can result in tumor-free margins, accomplish a radical resection, and treat the underlying primary sclerosing cholangitis when present. Hepatic epithelioid hemangioendothelioma is a rare tumor of vascular origin with a variable malignant potential. Excellent results have been reported with liver transplant for patients with unresectable hepatic epithelioid hemangioendothelioma, with 1-year and 10-year survival rates of 96% and 72%. Hepatoblastoma is the most common primary hepatic malignancy in children. The long-term survival rate after transplant ranges from 66% to 77% in patients with unresectable tumors and good response to chemotherapy. Metastatic liver disease is not an indication for liver transplant, with the exception of cases in which the primary tumor is a neuroendocrine tumor. Indication for liver transplant for hepatic metastasis from neuroendocrine tumors 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. Some recent data on liver transplant for unresectable hepatic metastases from colorectal cancer have reported limited survival benefits compared with previous reports. However, due to the high rate of tumor recurrence in a very short time after liver transplant, especially in the era of organ shortage, this indication has not been favored by the transplant community. The indications for liver transplant for nonhepatocellular carcinoma malignancy and its limitations have evolved dramatically over the past decades and will continue to be redefined through future research and investigations.

The Surgical Management of Small Bowel Neuroendocrine Tumors: Consensus Guidelines of the North American Neuroendocrine Tumor Society

Small bowel neuroendocrine tumors (SBNETs) have been increasing in frequency over the past decades, and are now the most common type of small bowel tumor. Consequently, general surgeons and surgical oncologists are seeing more patients with SBNETs in their practices than ever before. The management of these patients is often complex, owing to their secretion of hormones, frequent presentation with advanced disease, and difficulties with making the diagnosis of SBNETs. Despite these issues, even patients with advanced disease can have long-term survival. There are a number of scenarios which commonly arise in SBNET patients where it is difficult to determine the optimal management from the published data. To address these challenges for clinicians, a consensus conference was held assembling experts in the field to review and discuss the available literature and patterns of practice pertaining to specific management issues. This paper summarizes the important elements from these studies and the recommendations of the group for these questions regarding the management of SBNET patients.

Liver transplantation for metastatic liver tumors

Liver transplantation for metastatic neuroendocrine tumor in the liver used to be the main reason for liver transplantation for metastatic liver tumor. It is reported that liver transplantation in selected patients with non-resectable metastatic neuroendocrine tumor in the liver had favorable outcomes equivalent to liver transplantation for hepatocellular carcinoma. Recently, liver transplantation for colorectal liver metastasis has attracted attention. According to the SECA study in Oslo, liver transplantation for non-resectable colorectal liver metastasis had a high rate of recurrence but a favorable prognosis. Further discussion on patient selection, attempts at immunosuppressive therapy, and combination with chemotherapy and treatment at the time of relapse are required in order to improve the outcomes of liver transplantation for metastatic liver tumor.

Is there still a role for the hepatic locoregional treatment of metastatic neuroendocrine tumors in the era of systemic targeted therapies?

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) frequently present with distant metastases at the time of diagnosis and the liver is the most frequent site of spreading. The early identification of metastatic disease represents a major prognostic factor for GEP-NENs patients. Radical surgical resection, which is feasible for a minority of patients, is considered the only curative option, while the best management for patients with unresectable liver metastases is still being debated. In the last few years, a number of locoregional and systemic treatments has become available for GEP-NEN patients metastatic to the liver. However, to date only a few prospective studies have compared those therapies and the optimal management option is based on clinical judgement. Additionally, locoregional treatments appear feasible and safe for disease control for patients with limited liver involvement and effective in symptoms control for patients with diffuse liver metastases. Considering the lack of randomized controlled trials comparing the locoregional treatments of liver metastatic NEN patients, clinical judgment remains key to set the most appropriate therapeutic pathway. Prospective data may ultimately lead to more personalized and optimized treatments. The present review analyzes all the locoregional therapy modalities (i.e., surgery, ablative treatments and transarterial approach) and aims to provide clinicians with a useful algorithm to best treat GEP-NEN patients metastatic to the liver.

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.

Guidelines for the management of neuroendocrine tumours by the Brazilian gastrointestinal tumour group

Neuroendocrine tumours are a heterogeneous group of diseases with a significant variety of diagnostic tests and treatment modalities. Guidelines were developed by North American and European groups to recommend their best management. However, local particularities and relativisms found worldwide led us to create Brazilian guidelines. Our consensus considered the best feasible strategies in an environment involving more limited resources. We believe that our recommendations may be extended to other countries with similar economic standards.

Surgical Management of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) are a rare, heterogeneous group of neoplasms infamous for their endocrinopathies. Up to 90% of PNETs, however, are nonfunctional and are frequently detected incidentally on axial imaging during the evaluation of vague abdominal symptoms. Surgery remains the mainstay of therapy for patients diagnosed with both functional and nonfunctional PNETs. However, the multifaceted nature of PNETs challenges treatment decision making. In general, resection is recommended for patients with acceptable perioperative risk and amenable lesions.

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.

Surgical management for non-functional pancreatic neuroendocrine neoplasms with synchronous liver metastasis: A consensus from the Chinese Study Group for Neuroendocrine Tumors (CSNET)

Pancreatic neuroendocrine neoplasms (p-NENs) are slowly growing tumors with frequent liver metastasis. There is a variety of approaches to treat non-functional p-NENs with synchronous liver metastasis (LM) which complicates the determination of optimal treatment. Based on updated literature review, we discussed the treatment strategy determinants for p-NEN with LM. According to the resectability of primary tumor, the WHO 2010 grade classification and the radiological type of liver metastasis, the CSNET group reached agreements on a number of issues, including the following. Prior to treatment, biopsy is required to confirm pathology. Liver biopsy is important for more accurate grading of tumor and percutaneous core needle biopsy is more available than EUS-FNA. In patients with unresectable primary, surgical resection for liver-metastatic lesions should be avoided. Curative surgery is recommended for G1/G2 p-NET with type I LM and R1 resection also seems to improve overall survival rate. Cytoreductive surgery is recommended for G1/G2 p-NET with type II LM in select patients, and should meet stated requirements. Surgical resection for G1/G2 p-NET with type III LM and p-NEC with LM should be avoided, and insufficient evidence exists to guide the surgical treatment of G3 p-NET with LM. Liver transplantation may be an option in highly select patients. In addition, the optimal time for surgical approach is still required for more evidence.

Metastases of pancreatic neuroendocrine tumor to the liver as extremely rare indication for liver transplantation in children. Case report and review of the literature

Neuroendocrine tumors (NET) are extremely rare in children (0.75 cases per 100,000 children and adolescents a year) and the majority of these tumors are benign or present low grade of malignancy. According to the American registry Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute, less than 2% of all neuroendocrine tumors in children occur in the pancreas, making it a rare site for these tumors. The majority of them are found in children over 10years of age, especially those with malignant potential. Treatment of NET consists of different methods: surgery, somatostatin analogues and chemotherapy. Radical surgical resection remains the standard of treatment; however, it is not always feasible because of distant metastases. The authors present a case report of pancreatic NET with multiple metastases to the liver. The patient was treated with pancreatic resection and liver transplantation for liver metastases. Prior to liver transplantation, the patient was treated with somatostatin analogues, sunitinib and chemotherapy. Management of liver metastases with liver transplantation is discussed.

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.

Management of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (pNETs) are rare tumors that have a better prognosis than their exocrine counterpart, but frequently present with advanced disease. Management of pNETs has evolved considerably over the past decade. Surgical resection remains the only potentially curative option for patients with pNETs. Patients who have locoregionally advanced and/or metastatic pNETs require additional treatments. These include liver-directed (transarterial (chemo)-embolization, selective intraarterial radio therapy) and systemic therapies (somatostatin analogs, targeted therapy such as tyrosine-kinase inhibitors and mammalian target of rapamycin inhibitor, peptide receptor radionuclide therapy and cytotoxic chemotherapy). The aim of this article is to review the current treatment options as well as potential future therapeutic perspectives for patients with pNETs.

Liver transplantation for hepatobiliary malignancies: a new era of "Transplant Oncology" has begun

The indications of liver transplantation for hepatobiliary malignancies have been carefully expanded in a stepwise fashion, despite the fundamental limitations in oncological, immunological, and technical aspects. A new era of "Transplant Oncology," the fusion of transplant surgery and surgical oncology, has begun, and we stand at the dawn of a paradigm shift in multidisciplinary cancer treatment. For hepatocellular carcinoma, new strategies have been undertaken to select recipients based on biological and dynamic markers instead of conventional morphological and static parameters, opening the doors for a more deliberate expansion of the Milan criteria and locoregional therapies before liver transplantation. Neoadjuvant chemoradiation therapy followed by liver transplantation for unresectable perihilar cholangiocarcinoma developed by the Mayo Clinic provided excellent outcomes in a US multicenter study; however, the surgical indications are not necessarily universal and await international validation. Similarly, an aggressive multidisciplinary approach has been applied for other tumors, including intrahepatic cholangiocarcinoma, hepatoblastoma, liver metastases from colorectal and neuroendocrine primary and gastrointestinal stromal tumors as well as rare tumors, such as hepatic undifferentiated embryonal sarcoma and infantile choriocarcinoma. In conclusion, liver transplantation is an important option for hepatobiliary malignancies; however, prospective studies are urgently needed to ensure the appropriate patient selection, organ allocation and living donation policies, and administration of antineoplastic immunosuppression.

Pancreatic neuroendocrine tumors: Challenges in an underestimated disease

Pancreatic neuroendocrine tumours (PanNETs) are considered a relatively unusual oncologic entity. Due to its relative good prognosis, surgery remains the goal standard therapy not only in localized disease but also in the setting of locally or metastatic disease. Most of the patients are diagnosed in metastatic scenario, where multidisciplinary approach based on surgery, chemotherapies, liver-directed and/or molecular targeted therapies are commonly used. Owing to a deeper molecular knowledge of this disease, these targeted therapies are nowadays widely implemented, being the likely discovery of predictive biomarkers that would allow its use in other settings. This review is focused on describing the different classifications, etiology, prognostic biomarkers and multidisciplinary approaches that are typically used in PanNET.

Liver Resection for Non-Colorectal Liver Metastases - Standards and Extended Indications

Background

Due to the uncertain benefit of liver resection for non-colorectal liver metastases (NCLM), patient selection for surgery is generally difficult. Therefore, the aim of this article was to propose standard and extended indications for liver resection in this heterogeneous disease collective.

Methods

Review of the literature.

Results

The myriad of biologically different primary tumor entities as well as the mostly small and retrospective studies investigating the benefit of surgery for NCLM limits the proposal of general recommendations. Only resection of neuroendocrine liver metastases (NELM) appears to offer a clear benefit with a 5- and 10-year overall survival (OS) of 74 and 51%, respectively, in the largest series. Resection of liver metastases from genitourinary primaries might offer reasonable benefit in selected cases – with a 5-year OS of up to 61% for breast cancer and of 38% for renal cell cancer. The long-term outcome following surgery for other entities was remarkably poorer, e.g., gastric cancer, pancreatic cancer, and melanoma reached a 5-year OS of 20-42, 17-25, and about 20%, respectively.

Conclusion

Liver resection for NELM can be defined as a standard indication for the resection of NCLM while lesions of genitourinary origin might be defined as an extended indication.

Is There a Role for Liver Transplantation in Non-Colorectal Liver Metastases?

Due to the high blood flow, especially blood from the intestinal tract via the portal vein, the liver is a preferred organ for metastases. In case of advanced, irresectable liver metastases liver transplantation (LTX) remains an attractive option. However, due to high recurrence rates or a lack of data, up to date, metastases from neuroendocrine tumors (NETs) are the only accepted indication for LTX in non-colorectal liver metastases. In this regard, LTX is only justified in patients in which complete tumor resection (R0 resection) of the NET is achievable. A literature review revealed no clear patient selection criteria but transplantation should definitively achieve an R0 resection with complete freedom of tumor. The available data regarding the outcome following LTX for NETs show a comparable short- and long-term outcome for patients transplanted for other malignancies, e.g. hepatocellular carcinoma, or also benign indications in the high MELD (model for end-stage liver disease) era. Thus, most data prove a better post-transplant outcome and a lower recurrence rate in patients with a good differentiation of the tumor, a low proliferation index (Ki67), and a portal drainage of the NET.

Liver transplantation for the treatment of neuroendocrine liver metastases

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

Surgical management of neuroendocrine tumors

During the last decades an increase in the incidence of neuroendocrine tumors (NETs) was observed. Gastroenteropancreatic NETs represent the majority of NETs. Compared with their epithelial counterpart they usually have a more indolent behaviour and surgical resection improves survival. Tumor diameter is one of the main parameter in the decision making process for nonfunctioning forms. Generally, small lesions can be treated conservatively whereas larger tumors should be treated with standard surgical resection and lymphadenectomy. Functioning tumors should be resected regardless the dimension of the lesion. Locally advanced and metastatic disease should be also treated with extended resections, keeping in consideration the grading, size, Ki67, and presence of extra-abdominal disease. In the case of metastases the panel of operative treatment includes resection, ablation, up to liver transplantation.

Pancreatic neuroendocrine tumors: Nosography, management and treatment

Pancreatic neuroendocrine tumors (pNETs) represent about 7% of all NETs, 8.7% of gastroenteropancreatic NETs (GEP-NETs) and 1-2% of all pancreatic neoplasms. In the last two decades, the increased diagnosis of pNETs has generated great interest and the development of different classifications, grading and staging systems. Recently, several trials were performed in order to improve the knowledge of biomarkers and imaging and to provide an early diagnosis, but their role is still under debate. Nowadays, surgery represents the only curative approach for pNETs. Approximately 90% of pNETs are silent and non-functional; therefore, most patients are diagnosed in late stage and present metastatic (60%) or locally unresectable advanced disease (21%) with a poor prognosis. Not many therapeutic options are available for pNETs, with different treatments for G1-G2 and G3 tumors, because these diseases are still rare and trials are made up of few series of patients. At present, medical treatments is controversial. On these bases, we believe that a multidisciplinary team composed of surgeons, oncologists, endocrinologists, radiation oncologists, radiologists, pathologists and medicals nuclear is required. This paper presents a review of present state-of-the-art in the field of pNETs.

Role of Locoregional and Systemic Approaches for the Treatment of Patients with Metastatic Neuroendocrine Tumors

Although gastroenteropancreatic neuroendocrine tumors are often perceived as being indolent tumors, more than half of the patients will harbor liver metastases at the time of diagnosis. Gastroenteropancreatic neuroendocrine tumors have the potential to be aggressive and resistant to therapy, making the integration of both locoregional and systemic therapy even more critical in the treatment of patients with locally advanced or metastatic lesions. Over the last several years, significant advancements have been made in the surgical treatment, liver-directed therapy, and medical management of gastroenteropancreatic neuroendocrine tumors. While surgical resection is the cornerstone of therapy, cytoreductive surgery, orthotopic liver transplantation, local ablation, and intra-arterial therapy all improve the prognosis of patients suffering with locally advanced or metastatic disease. In addition, great strides have been made in the medical management of gastroenteropancreatic neuroendocrine tumors, particularly with the evolution of novel molecular targeted therapy, such as everolimus and sunitinib. Hence, gastroenteropancreatic neuroendocrine tumor is becoming a disease process requiring more of a multi-disciplinary approach with the integration of both locoregional and systemic therapies for improved outcomes.

Pancreatic Neuroendocrine Tumors: an Update

Pancreatic neuroendocrine tumors (pNETs) are rare and comprise only 1-2 % of all pancreatic neoplastic disease. Although the majority of these tumors are sporadic (90 %), pNETs can arise in the setting of several different hereditary genetic syndromes, most commonly multiple endocrine neoplasia type 1 (MEN1). The presentation of pNETs varies widely, with over 60 % having malignant distant disease at the time of initial diagnosis involving the liver or other distant sites. Functioning pNETs represent approximately 10 % of all pNETs, secrete a variety of peptide hormones, and are responsible for several clinical syndromes caused by profound hormonal derangement. Surgery remains the cornerstone of therapy and the only curative approach. It should be pursued for localized disease and for metastatic lesions amenable to resection. Multimodality therapies, including liver-directed therapies and medical therapy, are gaining increasing favor in the treatment of advanced pNETs. Their utility is multifold and spans from ameliorating symptoms of hormonal excess (functional pNETs) to controlling the local and systemic disease burden (non-functional pNETs). The recent introduction of target molecular therapy has promising results especially for the treatment of progressive well-differentiated G1/G2 tumor. In this review, we summarize the current knowledge and give an update on recent advancements made in the therapeutic strategies for pNETs.

Surgical approaches for liver metastases in carcinoid tumors

Liver is the commonest site for metastasis in patients with neuroendocrine tumors (NETs); it occurs in 45-95% of patients. Available treatment options include surgical resection, liver transplantation, chemotherapy and biotherapy. Surgery is the gold standard for curative therapy. Typically, a multidisciplinary approach is a cornerstone for decision making while dealing with this aggressive disease. This review will focus on the performance and safety of open, laparoscopic, and liver transplant surgical approaches in NETs patients with liver metastases.

Liver transplantation for secondary liver tumours

Cautious expansion of indications for liver transplantation

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.

Insulinoma: a multicenter, retrospective analysis of three decades of experience (1983-2014)

OBJECTIVE

To analyze the clinical features, diagnostic procedures, treatment, and clinical outcome of insulinomas diagnosed and treated in the period 1983-2014 in four Spanish hospitals.

METHODS

All patients with either biochemical and morphological criteria of insulinoma and/or histological demonstration of insulin-secreting tumor were included.

RESULTS

Twenty-nine patients [23 women (79.3%); mean age 48.7±17.4 years (range, 16-74)] were recruited. Twenty-six patients (89.7%) had sporadic tumors, and the rest (3 women, 10.3%) developed in the context of multiple endocrine neoplasia type 1. There were 3 (10.3%) multiple insulinomas, one associated with multiple endocrine neoplasia type 1, and two (6.9%) malignant insulinomas, both sporadic. Most patients (n=18, 62.1%) had fasting hypoglycemia, about a third (31%) both postprandial and fasting hypoglycemia, and 6.9% postprandial hypoglycemia only. Time to glucose nadir (37.3±6.5mg/dL) in the fasting test was 9.0±4.4h, with maximal insulin levels of 25.0±20.3μU/mL. Abdominal CT detected insulinoma in 75% of patients. Twenty-seven (93.1%) patients underwent surgery [enucleation, 18 (66.7%) and subtotal pancreatectomy, 9 (33.3%); tumor size, 1,7±0,7cm]. Surgery achieved cure in the majority (n=24, 88.9%) of patients.

CONCLUSION

In our setting, insulinoma is usually a benign, small, and solitary tumor, mainly affecting women aged 45-50 years, and usually localized with abdominal CT. The most commonly used surgical technique is enucleation, which achieves a high cure rate.

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.