Liver transplantation for unresectable neuroendocrine tumor liver metastases

[Well-differentiated neuroendocrine tumors of the digestive tract: Focus on pancreatic neuroendocrine tumors]

Pancreatic neuroendocrine tumors are rare tumors showing a rising incidence. They are well-differentiated tumors, classified by grade according to their Ki67 index value (grade 1 to 3). Pancreatic neuroendocrine tumors are mainly sporadic tumors but about 10% arise within endocrine tumor syndromes such as multiple endocrine neoplasia type 1. They can be responsible for functional syndromes or non-specific clinical symptoms depending on tumor extension. However, there is also an increase of incidental diagnoses of nonfunctional pancreatic neuroendocrine tumors with the widespread use of high-quality imaging techniques. About 50 % of pancreatic neuroendocrine tumors are diagnosed at a metastatic stage, with metastases often located in the liver. Chromogranin A, CT-scan and often an abdominal MRI, and functional imaging should be performed for tumor staging and follow-up. Imaging with PET/CT with 68Ga-labeled somatostatin analogues has the highest sensitivity for the diagnosis of pancreatic neuroendocrine tumors, while 18fluorodeoxyglucose PET/CT can sometimes be useful. Overall, they are rather indolent tumors with prolonged survival. Surgery is the recommended treatment in the localized setting, with the exception of small<2cm nonfunctional tumors that can be monitored with imaging techniques. For advanced tumors, there are several available treatments such as somatostatine analogues, chemotherapy, targeted therapies (sunitinib, everolimus), locoregional ablative therapies and Peptide Receptor Radiolabelled Therapy. The treatment strategy will depend on the initial tumor staging, tumor grade, aggressiveness and patient's choice.

A Comprehensive Review on Neuroendocrine Neoplasms: Presentation, Pathophysiology and Management

Neuroendocrine neoplasms (NENs) are a group of heterogeneous tumors with neuroendocrine differentiation that can arise from any organ. They account for 2% of all malignancies in the United States. A significant proportion of NEN patients experience endocrine imbalances consequent to increased amine or peptide hormone secretion, impacting their quality of life and prognosis. Over the last decade, pathologic categorization, diagnostic techniques and therapeutic choices for NENs-both well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs)-have appreciably evolved. Diagnosis of NEN mostly follows a suspicion from clinical features or incidental imaging findings. Hormonal or non-hormonal biomarkers (like serum serotonin, urine 5-HIAA, gastrin and VIP) and histology of a suspected NEN is, therefore, critical for both confirmation of the diagnosis and classification as an NET or NEC. Therapy for NENs has progressed recently based on a better molecular understanding, including the involvement of mTOR, VEGF and peptide receptor radionuclide therapy (PRRT), which add to the growing evidence supporting the possibility of treatment beyond complete resection. As the incidence of NENs is on the rise in the United States and several other countries, physicians are more likely to see these cases, and their better understanding may support earlier diagnosis and tailoring treatment to the patient. We have compiled clinically significant evidence for NENs, including relevant changes to clinical practice that have greatly updated our diagnostic and therapeutic approach for NEN patients.

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

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

Liver transplantation in gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors are part of a heterogeneous group of tumors located in organs such as the gastrointestinal tract (GIT), lungs, thymus, thyroid, and adrenal glands. The most prevalent sites are the small intestine, cecal appendix, and pancreas. More than 50% of these tumors are associated with metastases at the time of diagnosis. Neuroendocrine tumors are classified according to the degree of cell differentiation and the histopathological proliferation index of the lesion. Neuroendocrine tumors can be well differentiated or poorly differentiated. G3 tumors are characterized by Ki-67 expression greater than 20% and can be either well differentiated (G3 NET) or poorly differentiated (G3 NEC). Neuroendocrine carcinoma (NEC G3) is subdivided into small-cell and large-cell types. When neuroendocrine tumors present clinical and compressive symptoms, carcinoid syndrome is evident. Carcinoid syndrome occurs when the tumor produces neuroendocrine mediators that cannot be metabolized by the liver due to either the size of the tumor or their secretion by the liver itself. Several therapeutic strategies have been described for the treatment of metastatic neuroendocrine tumors, including curative or palliative surgical approaches, peptide receptor radionuclide therapy, percutaneous therapy, systemic chemotherapy, and radiotherapy. Liver surgery is the only approach that can offer a cure for metastatic patients. Liver metastases must be completely resected, and in this context, orthotopic liver transplantation has gained prominence for yielding very promising outcomes in selected cases. The aim of this study is to review the literature on OLT as a form of treatment with curative intent for patients with gastroenteropancreatic neuroendocrine tumors with liver metastasis.

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

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

Management of Metastatic GEPNETs

The chief causes of death of patients with GEPNETs are liver failure from hepatic replacement by tumor in the majority and bowel obstruction in the remainder. Many patients are with liver metastases are actually eligible for hepatic cytoreductive operations, even if they have numerous bilobar metastases and extra-hepatic disease, provided that greater than 70% of the liver tumor volume can be removed. This can often be done by combinations of parenchyma-sparing enucleations, wedge resections and radio frequency ablations. Patients with higher liver tumor burden can be treated with intra-arterial therapies, such as embolization and chemoembolization. Patients with peritoneal carcinomatosis are recommended to undergo cytoreductive operations including peritoneal stripping and bowel resections. Consensus guidelines by experts recommend bisphosphonate therapy for patients with bone metastases, reserving surgical treatment for patients with mechanical issues and/or potential spinal cord compression. Radiation can be employed for isolated painful metastases. PRRT may be an emerging therapy for treatment of bone metastases.

Postrecurrence Survival After Liver Transplantation for Liver Metastases From Neuroendocrine Tumors

BACKGROUND

Liver metastases from neuroendocrine tumors (NETs) is an accepted indication for liver transplantation (LT). Despite strict patient selection, post-LT recurrence is observed in 30-50% of cases. Postrecurrence survival is poorly investigated as well as factors influencing postrecurrence outcomes.

METHODS

Consecutive patients treated at a single Institution for post-LT recurrence of NET between Jan 1st, 2004 and Dec 31th, 2018 were included. Baseline patients' characteristics, data on the primary tumor, pretransplant therapies, posttransplant recurrence and treatments and long-term outcomes were prospectively collected and retrospectively analyzed.

RESULTS

Thirty-two patients presented with post-LT NET recurrence occurring 82.9 months (IQR 29.4-119.1) from LT, and the most common sites were abdominal lymph nodes (59.4%), peritoneum (6.3%) and lungs (6.3%). Fourteen patients (43.8%) underwent surgery with radical intent. Five- and 10-years survival after recurrence were 76.3% and 45.5%, respectively. Only time from LT to recurrence had a significant impact on post recurrence survival, being 5-years OS 89.5% versus 0% for patients recurring > 24 months after LT versus ≤ 24 months, respectively (p=.001). Moreover, for patients with Mib-1 > 2% at recurrence, 5-years OS was 87.5% versus 0% for those undergoing surgery versus loco-regional or systemic treatments (p=0.011).

CONCLUSIONS

The presented results, although based on a retrospective and relatively small series, show that excellent long-term survival is observed after post-LT NET recurrence, particularly in those patients recurring long after LT (> 24 months). An aggressive surgical treatment might result in a new chance of cure for a selected subgroup of patients.

Surgical management of Zollinger-Ellison syndrome: Classical considerations and current controversies

Zollinger-Ellison syndrome (ZES) is characterized by gastric acid hypersecretion causing severe recurrent acid-related peptic disease. Excessive secretion of gastrin can now be effectively controlled with powerful proton pump inhibitors, but surgical management to control gastrinoma itself remains controversial. Based on a thorough literature review, we design a surgical algorithm for ZES and list some significant consensus findings and recommendations: (1) For sporadic ZES, surgery should be routinely undertaken as early as possible not only for patients with a precisely localized diagnosis but also for those with negative imaging findings. The surgical approach for sporadic ZES depends on the lesion location (including the duodenum, pancreas, lymph nodes, hepatobiliary tract, stomach, and some extremely rare sites such as the ovaries, heart, omentum, and jejunum). Intraoperative liver exploration and lymphadenectomy should be routinely performed; (2) For multiple endocrine neoplasia type 1-related ZES (MEN1/ZES), surgery should not be performed routinely except for lesions > 2 cm. An attempt to perform radical resection (pancreaticoduodenectomy followed by lymphadenectomy) can be made. The ameliorating effect of parathyroid surgery should be considered, and parathyroidectomy should be performed first before any abdominal surgery for ZES; and (3) For hepatic metastatic disease, hepatic resection should be routinely performed. Currently, liver transplantation is still considered an investigational therapeutic approach for ZES. Well-designed prospective studies are desperately needed to further verify and modify the current considerations.

An update on the management of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are a rare and heterogeneous group of neoplasia and differ in their clinical presentation, behavior, and prognosis based on both histological features and cancer stage at the time of diagnosis. Although small-sized tumors can be surgically resected, locally advanced and metastatic tumors confer a poor prognosis. In addition, only limited treatment options are available to the latter group of patients with PNETs, such as hormonal analogs, cytotoxic agents, and targeted therapy. In selected patients, liver-directed therapies are also used. As expected, clinicians taking care of these patients are challenged to develop an effective and comprehensive treatment strategy for their patients amid a wide variety of treatment modalities. Targeted therapy for PNETs is limited to sunitinib and everolimus. Presently, a number of clinical studies are ongoing to assess the efficacy of newer targeted agents alone and in combination with previous agents for the treatment of advanced PNETs. The authors reviewed the current treatment and also discussed the emerging agents and emphasized the need to identify biomarkers.

Liver transplantation in patients with liver metastases from neuroendocrine tumors

The prevalence of metastatic disease in neuroendocrine tumors (NETs) is very high (60-80%) and cancer-related death among these patients is generally due to metastatic disease. Numerous treatment options for cure and disease control have been investigated for patients with neuroendocrine liver metastases (NELM). Despite the success of liver directed therapy on slowing tumor progression and palliating symptoms, the chance of being cured by liver resection is 40-50% and only roughly 20% of patients have potentially resectable disease. As such, there has been interest in liver transplantation (LT) as a potentially curative option for patients with unresectable disease. Several criteria have been proposed in order to balance long-term outcomes of patients with NELM and the problem of organ shortage including the Milan-NET criteria, the UNOS criteria and the ENETS guidelines. In the most representative studies, recurrence rate after LT has ranged from 30% to 60% with a 5-year OS ranging from 50% to 97%. This large variability is due to the retrospective nature of the studies available, which used different inclusion criteria. As such, outcomes and the prognostic factors associated with LT for NELM warrant further investigation.

[Oligometastases of neuroendocrine tumors-extent of surgery]

Neuroendocrine tumors (NETs) are rare neoplasms, which represent complex challenges in diagnosis and treatment. Even in the metastatic stage there are important differences in the type of tumor in comparison to gastrointestinal and pancreatic adenocarcinomas. Therefore, the disease courses are substantially different depending on the grade of differentiation. Even in the metastatic stage the 5‑year survival rates of G1 tumors is up to 83%. Approximately 20% of small intestine NETs additionally show hormone activity, which can compromise survival and the quality of life. For individual treatment decisions the special tumor biology of these tumors must be taken into consideration more so than for other tumor entities. Surgery always becomes important for these tumors when a R0 resection appears possible. Oligometastasis of the liver and the lymph drainage system can be meaningfully approached by surgical treatment. In selected patients with an isolated liver involvement, a liver transplantation can be considered; however, even tumor debulking can lead to improvement in the quality of life and survival, especially for hormone active tumors with a carcinoid syndrome which cannot be conservatively controlled. The aim of this review is to present the value of surgical treatment options in the case of (oligo)metastasized NETs.

Analysis of B-ultrasound and contrast-enhanced ultrasound characteristics of different hepatic neuroendocrine neoplasm

BACKGROUND

Hepatic neuroendocrine neoplasm (hNEN) is a highly heterogeneous tumor. The exact identification of the source and malignant degree of hNEN is important. However, there is a lack of information regarding diagnosis of hNEN with imaging. In addition, no studies have compared the imaging between hNEN and hepatocellular carcinoma (HCC) and among different sources and malignant degrees of hNEN.

AIM

To compare the ultrasound characteristics between hNEN and HCC and among different sources and malignant degrees of hNEN.

METHODS

A total of 55 patients with hNEN were recruited and defined as the hNEN group. Among them, 35 cases of hNET were defined as the hNET group. Twenty cases of hepatic neuroendocrine carcinoma (hNEC) were defined as the hNEC group. Among the 55 lesions, 29 were transferred from the pancreas, 20 were from the gastrointestinal tract, and six were from other sites. In total, 55 patients with HCC were recruited and defined as the HCC group. The characteristic differences of B-mode ultrasound and contrast-enhanced ultrasound (CEUS) between hNEN and HCC and among different sources and malignant degrees of hNEN were compared.

RESULTS

In the hNEN group, the proportions of multiple liver lesions, unclear borders, and high echo lesions were higher than those in the HCC group. The proportions of non-uniform echo and peripheral acoustic halo were lower than those in the HCC group (P < 0.05). The washout to iso-enhancement time and washout to hypo-enhancement time were lower than those in the HCC group (P < 0.05). The characteristics of B-ultrasound and CEUS among different sources of hNEN were similar, and the differences were not statistically significant (P > 0.05). B-mode ultrasound characteristics of hNET and hNEC were similar. The proportions of low enhancement at portal venous phase, non-uniform enhancement forms, and combined tumor vasculature in the hNEC group were larger than those in the hNEN group (P < 0.05).

CONCLUSION

Compared with HCC, hNEN showed multiple intrahepatic lesions, uniform high echo, uniform high enhancement at arterial phase, and rapid washout. Low enhancement at portal venous phase, overall non-uniform enhancement form, and the proportion of combined tumor vasculature in hNEC were larger than those in hNET.

Treatment options for PNET liver metastases: a systematic review

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are rare pancreatic neoplasms. About 40-80% of patients with PNET are metastatic at presentation, usually involving the liver (40-93%). Liver metastasis represents the most significant prognostic factor. The aim of this study is to present an up-to-date review of treatment options for patients with liver metastases from PNETs.

METHODS

A systematic literature search was performed using the PubMed database to identify all pertinent studies published up to May 2018.

RESULTS

The literature search evaluated all the therapeutic options for patients with liver metastases of PNETs, including surgical treatment, loco-regional therapies, and pharmacological treatment. All the different treatment options showed particular indications in different presentations of liver metastases of PNET. Surgery remains the only potentially curative therapeutic option in patients with PNETs and resectable liver metastases, even if relapse rates are high. Efficacy of medical treatment has increased with advances in targeted therapies, such as everolimus and sunitinib, and the introduction of radiolabeled somatostatin analogs. Several techniques for loco-regional control of metastases are available, including chemo- or radioembolization.

CONCLUSIONS

Treatment of patients with PNET metastases should be multidisciplinary and must be personalized according to the features of individual patients and tumors.

CT evaluation of response in advanced gastroenteropancreatic neuroendocrine tumors treated with long-acting-repeatable octreotide: what is the optimal size variation threshold?

OBJECTIVE

To identify a reliable early indicator of deriving progression-free survival (PFS) benefit in patients with advanced gastroenteropancreatic neuroendocrine tumors (GEP-NETs) treated with octreotide long-acting repeatable (LAR).

METHODS

We investigated the images of 50 patients with well-differentiated advanced GEP-NETs treated with LAR octreotide and underwent baseline and follow-up thoracic, abdominal, and pelvic computed tomography. Receiver-operating characteristic (ROC) analysis and the Kaplan-Meier method were used to identify the optimal threshold to distinguish between those with and without significant improvement of PFS.

RESULTS

The optimal threshold for determining a response to octreotide LAR was -10% ΔSLD, with a sensitivity and specificity of 85.7% and 80%, respectively. At this threshold, 19 patients were responders and 31 were non-responders; the median PFS was 20.2 and 7.6 months in responders and non-responders (hazard ratio, 2.66; 95% confidence interval, 1.32-5.36).

CONCLUSION

A 10% shrinkage in tumor size is an optimal early predictor of response to octreotide LAR in advanced GEP-NETs.

KEY POINTS

• Octreotide LAR can significantly prolong PFS among patients with well-differentiated advanced GEP-NETs. • No optimal tumor size-based response criteria are reported in GEP-NETs with octreotide. • Ten percent tumor shrinkage is a reliable indicator of the response to octreotide for advanced GEP-NETs.

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.

Pediatric liver transplantation for hepatocellular cancer and rare liver malignancies: US multicenter and single-center experience (1981-2015)

A tenth of all pediatric liver transplantations (LTs) are performed for unresectable liver malignancies, especially the more common hepatoblastoma (HBL). Less understood are outcomes after LT for the rare hepatocellular carcinoma, nonhepatoblastoma embryonal tumors (EMBs), and slow growing metastatic neuroendocrine tumors of childhood. Pediatric LT is increasingly performed for rare unresectable liver malignancies other than HBL. We performed a retrospective review of outcomes after LT for malignancy in the multicenter US Scientific Registry of Transplant Recipients (SRTR; n = 677; 1987-2015). We then reviewed the Children's Hospital of Pittsburgh (CHP; n = 74; 1981-2014) experience focusing on LT for unresectable hepatocellular cancer (HCC), EMBs, and metastatic liver tumors (METS). HBL was included to provide reference statistics. In the SRTR database, LT for HCC and HBL increased over time (P < 0.001). Compared with other malignancies, the 149 HCC cases received fewer segmental grafts (P < 0.001) and also experienced 10-year patient survival similar to 15,710 adult HCC LT recipients (51.6% versus 49.6%; P = 0.848, not significant [NS], log-rank test). For 22 of 149 cases with incidental HCC, 10-year patient survival was higher than 127 primary HCC cases (85% [95% confidence interval (CI), 70.6%-100%] versus 48.3% [95% CI, 38%-61%]; P = 0.168, NS) and similar to 3392 biliary atresia cases (89.9%; 95% CI, 88.7%-91%). Actuarial 10-year patient survival for 17 EMBs, 10 METS, and 6 leiomyosarcoma patients exceeded 60%. These survival outcomes were similar to those seen for HBL. At CHP, posttransplant recurrence-free and overall survival among 25 HCC, 17 (68%) of whom had preexisting liver disease, was 16/25 or 64%, and 9/25 or 36%, respectively. All 10 patients with incidental HCC and tumor-node-metastasis stage I and II HCC survived recurrence-free. Only vascular invasion predicted poor survival in multivariate analysis (P < 0.0001). A total of 4 of 5 EMB patients (80%) and all patients with METS (neuroendocrine-2, pseudopapillary pancreatic-1) also survived recurrence-free. Among children, LT can be curative for unresectable HCC confined to the liver and without vascular invasion, incidental HCC, embryonal tumors, and metastatic neuroendocrine tumors. Liver Transplantation 23 1577-1588 2017 AASLD.

Treatment challenges in and outside a specialist network setting: Pancreatic neuroendocrine tumours

Pancreatic Neuroendocrine Neoplasms comprise a group of rare tumours with special biology, an often indolent behaviour and particular diagnostic and therapeutic requirements. The specialized biochemical tests and radiological investigations, the complexity of surgical options and the variety of medical treatments that require individual tailoring, mandate a multidisciplinary approach that can be optimally achieved through an organized network. The present study describes currents concepts in the management of these tumours as well as an insight into the challenges of delivering the pathway in and outside a Network.

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.

Digestive neuroendocrine neoplasms: A 2016 overview

Digestive neuroendocrine neoplasms (DNENs) have an incidence of 2.39 per 100,000 inhabitants per year, and a prevalence of 35 cases per 100,000; the gap between these rates is to be referred to the relatively long survival that characterizes the majority of these tumors, which can be thus considered as chronic oncological diseases. Up to 80% of patients are stage IV since the first diagnosis, presenting a 5-yr overall survival rate of 35%-55% and a twice higher mortality than limited disease. DNENs express somatostatin receptors in more than 80% of cases, detected through immunohistochemistry or functional imaging tests (FITs). This feature identifies patients who may benefit from "cold" somatostatin analogs (SSAs) or peptide receptors radionuclide therapy, although SSAs are sometimes used also with a negative uptake at FITs. The therapeutic options have been recently increased after the identification of molecular pathways involved in DNENs pathogenesis, and the subsequent use of targeted therapies (i.e., Everolimus and Sunitinib) for these neoplasms. This review offers an overview about pancreatic and small bowel NENs, critically underlining the issues that still need to be clarified and the future perspectives to be investigated.

Present and future role of surgery in metastatic gastrointestinal malignancies

PURPOSE OF REVIEW

Metastases from gastrointestinal malignancies are systemic or abdominal disseminations of cancer cells. From a biological perspective surgical resections are questionable but case series show that for some tumour types, surgery influences survival outcome. This review focuses on management and indications for surgery in recent literature of these metastatic gastrointestinal malignancies.

RECENT FINDINGS

A few gastrointestinal malignancies have emerged to be candidates for surgery in case of metastatic disease. Surgery can be considered in selected cases with liver metastases or abdominal dissemination of colorectal cancer, metastases from gastrointestinal stromal tumours or neuroendocrine tumours. On the contrary, recent publications do not support surgery for metastatic disease of any other gastrointestinal origin. The literature has ample examples of small series and anecdotal cases of successful surgical interventions for most tumour types but no new evidence has been presented to support broader indications for surgery.

SUMMARY

The evidence base for surgery of different metastatic gastrointestinal malignancies is unchanged. There are some clarifications when to perform surgery and the timing of surgery in regard to combined treatments. No new tumour types are added to potential candidates for surgery.

Subgroup analysis of patients with G2 gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors (NET) are malignancies with an increasing incidence rate. NETs are graded or classified by the expression level of Ki67, a proliferation marker in Grade 1 and 2 tumors. Out of 120 patients who visited our hospital between 2003 and 2012, 40 were classified as G2 NET. This study was mainly designed to investigate a new threshold for optimising the Ki67 system. Patients were subdivided into two new groups according to Ki67 (group 1 = 3-9%, group 2 = 10-20%). Twenty-five patients were allocated to group 1 and 15 to group 2. The primary tumor originated in 46% from the foregut and 68% NET were functionally active. Patients were treated in 88 versus 60% by surgery, 48 versus 80% by somatostatin analogs, 0 versus 20% by chemotherapy, 2,5 versus 0% by Everolimus and 32 versus 47% underwent peptide receptor radionuclide therapy. Group 1 patients showed a significantly (p = 0.01) better survival compared with group 2 and also a significant difference of Chromogranin A (p = 0.03) and alkaline phosphatase (p = 0.01). In addition, all patients with elevated lactate dehydrogenase showed a significantly (p = 0.03) shorter survival. Prognostic relevance of G2 NETs may be improved by using a new boundary. Patients with Ki67 of 3-9% showed a better response to current treatment methods and significantly longer survival compared to group 2. Thus, our data clearly show that patients with higher G2 proliferation index should be treated differently. Finally, LDH has been found to be a new prognostic factor in patients with G2 NET.

Long-Term Survival with Long-Acting Somatostatin Analogues Plus Aggressive Cytoreductive Surgery in Patients with Metastatic Neuroendocrine Carcinoma

BACKGROUND

Long-acting somatostatin analogues (S-LAR) improve recurrence-free survival in patients with metastatic neuroendocrine tumor (NET) from gastrointestinal (GI) primary, but their impact on overall survival when combined with aggressive cytoreductive surgery is unclear.

STUDY DESIGN

We reviewed our institutional cancer database to identify patients who underwent cytoreductive surgery for metastatic NET from GI primary between December 1997 and June 2013. Additionally, a cohort selected from 3,384 metastatic neuroendocrine cases in the SEER-Medicare database (January 2003 to December 2009) was used to verify and expand on our results.

RESULTS

Most of the 49 patients from our institution had primary lesions in the small intestine (22 of 49 [44.9%]) or pancreas (14 of 49 [28.6%]); 37 patients (75.5%) had metastatic disease at initial diagnosis. These patients underwent 1 (32 of 49 [65.3%]), 2 (11 of 49 [22.4%]), or at least 3 (6 of 49 [12.3%]) surgical procedures; 33 patients (67.3%) underwent resection plus ablation, 19 (38.7%) underwent major hepatectomy, and 34 (69.4%) received S-LAR (29.4% administered preoperatively). Median follow-up was 112 months. Rates of 1-, 5-, 10-, and 15-year disease-specific survival (DSS) were 94%, 78%, 64%, and 31%, respectively, in the 34 patients undergoing aggressive cytoreductive surgery plus S-LAR. Of the SEER-Medicare population, 1,741 patients met inclusion criteria. The DSS for the 104 patients treated with combination therapy was 68.3% at 5 years and 60.6% at 10 years, as compared with 54.7% and 51.8%, respectively, for the 202 patients receiving surgery alone, and 50.0% and 36.0%, respectively, for the 342 patients receiving S-LAR alone (p < 0.0001). The group receiving neither treatment (n = 1,093) had 5-year and 10-year DSS of 34.3% and 26.3%, respectively.

CONCLUSIONS

Long-acting somatostatin analogues combined with aggressive cytoreductive surgery improves the long-term survival of select patients with metastatic NET from GI primary.

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.

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.