Fluorouracil, doxorubicin, and streptozocin in the treatment of patients with locally advanced and metastatic pancreatic endocrine carcinomas

[Gastroenteropancreatic neuroendocrine neoplasms-Heterogeneity, management and perspectives of treatment and research]

The term neuroendocrine neoplasms (NEN) encompasses a molecularly and biologically very heterogeneous group of tumors, which have in common their origin in neuroendocrine cells. The also very heterogeneous subgroup of gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) is the best classified and investigated group. This article provides a systematic review of the current classification, diagnostics and treatment options of GEP-NEN. In order to achieve a better overview, it was consciously decided not to use an approach based on the primary localization. Instead, a thematic organization according to classification, clinical phenotype, diagnostics and treatment was chosen.

How I treat neuroendocrine tumours

Neuroendocrine tumours (NETs) constitute a heterogeneous group of neoplasms characterised by variable endocrine activity and somatostatin receptor expression, with the latter allowing the use of targeted therapeutic concepts. Currently accepted treatment strategies for advanced well-differentiated NET include somatostatin analogues octreotide and lanreotide, peptide receptor radionuclide therapy using radiolabelled somatostatin analogues, mammalian target of Rapamycin inhibitor everolimus, tyrosine kinase inhibitor sunitinib, interferon alpha and classical cytostatic, such as streptozotocin-based and temozolomide-based treatment. Indication, use and approval of these treatments differ based on primary tumour origin, grading and symptomatic burden and require an optimised multidisciplinary cooperation of medical oncologists, endocrinologists and nuclear medicine specialists. Interestingly, hot topics in oncology including immunotherapy and use of next-generation-sequencing techniques currently play a minor role for the treatment of NETs. The recent revision of the WHO classification including the recognition of the novel NET G3 category allows for potentially more tailored treatment strategies in the near future. However, this new entity also poses a therapeutic challenge as only limited data are currently available. The present article aims to provide an overview on our personal treatment concepts for advanced NETs with a focus on tumours of gastroenteropancreatic origin.

The North American Neuroendocrine Tumor Society Consensus Guidelines for Surveillance and Medical Management of Pancreatic Neuroendocrine Tumors

This article is the result of the North American Neuroendocrine Tumor Society consensus conference on the medical management of pancreatic neuroendocrine tumors from July 19 to 20, 2018. The guidelines panel consisted of medical oncologists, pathologists, gastroenterologists, endocrinologists, and radiologists. The panel reviewed a series of questions regarding the medical management of patients with pancreatic neuroendocrine tumors as well as questions regarding surveillance after resection. The available literature was reviewed for each of the question and panel members voted on controversial topics, and the recommendations were included in a document circulated to all panel members for a final approval.

Systemic Treatment Selection for Patients with Advanced Pancreatic Neuroendocrine Tumours (PanNETs)

Pancreatic neuroendocrine tumours (PanNETs) are rare diseases and a good example of how research is not only feasible, but also of crucial importance in the scenario of rare tumours. Many clinical trials have been performed over the past two decades expanding therapeutic options for patients with advanced PanNETs. Adequate management relies on optimal selection of treatment, which may be challenging for clinicians due to the fact that multiple options of therapy are currently available. A number of therapies already exist, which are supported by data from phase III studies, including somatostatin analogues and targeted therapies (sunitinib and everolimus). In addition, chemotherapy remains an option, with temozolomide and capecitabine being one of the most popular doublets to use. Peptide receptor radionuclide therapy was successfully implemented in patients with well-differentiated gastro-entero-pancreatic neuroendocrine tumours, but with certain questions waiting to be solved for the management of PanNETs. Finally, the role of immunotherapy is still poorly understood. In this review, the data supporting current systemic treatment options for locally advanced or metastatic PanNETs are summarized. Strategies for treatment selection in patients with PanNETs based on patient, disease, or drug characteristics is provided, as well as a summary of current evidence on prognostic and predictive biomarkers. Future perspectives are discussed, focusing on current and forthcoming challenges and unmet needs of patients with these rare tumours.

Pancreatic neuroendocrine tumors G3 and pancreatic neuroendocrine carcinomas: Differences in basic biology and treatment

In 2017 the World Health Organization revised the criteria for classification of pancreatic neuroendocrine neoplasms (pNENs) after a consensus conference at the International Agency for Research on Cancer. The major change in the new classification was to subclassify the original G3 group into well-differentiated pancreatic neuroendocrine tumors G3 (pNETs G3) and poorly differentiated pancreatic neuroendocrine carcinomas (pNECs), which have been gradually proven to be completely different in biological behavior and clinical manifestations in recent years. In 2019 this major change subsequently extended to NENs involving the entire digestive tract. The updated version of the pNENs grading system marks a growing awareness of these heterogeneous tumors. This review discusses the clinicopathological, genetic and therapeutic features of poorly differentiated pNECs and compare them to those of well-differentiated pNETs G3. For pNETs G3 and pNECs (due to their lower incidence), there are still many problems to be investigated. Previous studies under the new grading classification also need to be reinterpreted. This review summarizes the relevant literature from the perspective of the differences between pNETs G3 and pNECs in order to deepen understanding of these diseases and discuss future research directions.

Medical Treatment of Advanced Pancreatic Neuroendocrine Neoplasms

Pancreatic neuroendocrine neoplasms (panNENs) are relatively rare but their incidence has increased almost sevenfold over the last four decades. Neuroendocrine neoplasms are classified according to their histologic differentiation and their grade. Their grade is based on their Ki-67 proliferation index and mitotic index. Their prognosis is highly variable according to these elements and treatments also vary according to their classification. Surgery is the only curative treatment for localized and advanced panNENs and offers a better prognosis than non-surgical treatments. In the case of an advanced panNEN without the possibility of resection and/or ablation, medical treatment remains the cornerstone for improving survival and preserving quality-of-life. PanNENs are considered as chemosensitive tumors, unlike midgut neuroendocrine tumors. Thus, panNENs can be treated with chemotherapy, but targeted therapies and somatostatin analogs are also treatment options. The scarcity and heterogeneity of NENs make their management difficult. The present review aims to clarify the medical treatments currently available for advanced panNENs, based on their characteristics, and to propose a treatment algorithm.

Treatment-related changes in neuroendocrine tumors as assessed by textural features derived from 68Ga-DOTATOC PET/MRI with simultaneous acquisition of apparent diffusion coefficient

Background

Neuroendocrine tumors (NETs) frequently overexpress somatostatin receptors (SSTRs), which is the molecular basis for ⁶⁸Ga-DOTATOC positron-emission tomography (PET) and radiopeptide therapy (PRRT). However, SSTR expression fluctuates and can be subject to treatment-related changes. The aim of this retrospective study was to assess, which changes in PET and apparent diffusion coefficient (ADC) occur for different treatments and if pre-therapeutic ⁶⁸Ga-DOTATOC-PET/MRI was able to predict treatment response to PRRT.

Methods

Patients with histopathologically confirmed NET, at least one liver metastasis > 1 cm and at least two ⁶⁸Ga-DOTATOC-PET/MRI including ADC maps were eligible. ⁶⁸Ga-DOTATOC-PET/MRI of up to 5 liver lesions per patients was subsequently analyzed. Extracted features comprise conventional PET parameters, such as maximum and mean standardized uptake value (SUVmax and SUVmean) and ADC values. Furthermore, textural features (TFs) from both modalities were extracted. In patients with multiple ⁶⁸Ga-DOTATOC-PET/MRI a pair of 2 scans each was analyzed separately and the parameter changes between both scans calculated. The same image analysis was performed in patients with ⁶⁸Ga-DOTATOC-PET/MRI before PRRT. Differences in PET and ADC maps parameters between PRRT-responders and non-responders were compared using Mann-Whitney test to test differences among groups for statistical significance.

Results

29 pairs of ⁶⁸Ga-DOTATOC-PET/MRI scans of 18 patients were eligible for the assessment of treatment-related changes. In 12 cases patients were treated with somatostatin analogues between scans, in 9 cases with PRRT and in 2 cases each patients received local treatment, chemotherapy and sunitinib. Treatment responders showed a statistically significant decrease in lesion volume and a borderline significant decrease in entropy on ADC maps when compared to non-responders. Patients treated with standalone SSA showed a borderline significant decrease in mean and maximum ADC, compared to patients treated with PRRT. No parameters were able to predict treatment response to PRRT on pre-therapeutic ⁶⁸Ga-DOTATOC-PET/MRI.

Conclusions

Patients responding to current treatment showed a statistically significant decrease in lesion volume on ADC maps and a borderline significant decrease in entropy. No statistically significant changes in PET parameters were observed. No PET or ADC maps parameters predicted treatment response to PRRT. However, the sample size of this preliminary study is small and further research needed.

Phase 1 dose escalation trial of TAS-102 (trifluridine/tipiracil) and temozolomide in the treatment of advanced neuroendocrine tumors

Neuroendocrine tumors (NETs) are understudied and have limited systemic treatment options. Prior studies for patients with advanced NETs have demonstrated promising results when antimetabolite agents, including fluoropyrimidines, were combined with temozolomide TMZ. TAS-102 (trifluridine/tipiracil) is an antineoplastic agent that is non-cross resistant with 5-fluorouracil and capecitabine and that has a different toxicity profile. This study evaluated the safety of TAS-102 in combination with TMZ in patients in neuroendocrine tumors. Escalating doses of TMZ (100, 150 and 200 mg/m²) on days 8-12 were given in combination with TAS-102 (35 mg/m² twice a day) on days 1-5 and 8-12 of a 28 day cycle in subjects with advanced NETs. Primary endpoints were safety and determination of maximum tolerated dose (MTD). Growth factor support was mandated starting with level 2 to avoid treatment delays. Fifteen evaluable subjects were enrolled in the phase 1 study. No dose limiting toxicities (DLTs) were observed on level 1. One DLT was observed on level 2 (grade 3 fatigue and inability to resume treatment), and 1 on level 3 (grade 4 thrombocytopenia). The most common grade ≥ 3 adverse events included neutropenia (33%), lymphopenia (27%), and thrombocytopenia (27%). Disease control rate of 92% and partial response rate of 8% were observed in 13 evaluable subjects. This study established MTD of TAS-102 (35 mg/m² twice daily) and TMZ (200 mg/m² daily). This regimen was well tolerated. Early signs of clinically meaningful activity were observed. Further evaluation of the efficacy of this regimen is warranted.

Neoadjuvant Capecitabine/Temozolomide for Locally Advanced or Metastatic Pancreatic Neuroendocrine Tumors

OBJECTIVES

The combination chemotherapy regimen capecitabine/temozolomide (CAPTEM) is efficacious for metastatic well-differentiated pancreatic neuroendocrine tumors (PNETs), but its role in the neoadjuvant setting has not been established.

METHODS

The outcomes of all patients with locally advanced or resectable metastatic PNETs who were treated with neoadjuvant CAPTEM between 2009 and 2017 at 2 high-volume institutions were retrospectively reviewed.

RESULTS

Thirty patients with locally advanced PNET (n = 10) or pancreatic neuroendocrine hepatic metastases (n = 20) received neoadjuvant CAPTEM. Thirteen patients (43%) exhibited partial radiographic response (PR), 16 (54%) had stable disease, and 1 (3%) developed progressive disease. Twenty-six (87%) patients underwent resection (pancreatectomy [n = 12], combined pancreatectomy and liver resection [n = 8], or major hepatectomy alone [n = 6]); 3 (18%) declined surgery despite radiographic PR, and 1 (3%) underwent aborted pancreatoduodenectomy. Median primary tumor size was 5.5 cm, and median Ki-67 index was 3.5%. Rates of PR were similar across tumor grades (P = 0.24). At median follow-up of 49 months, median progression-free survival was 28.2 months and 5-year overall survival was 63%.

CONCLUSIONS

Neoadjuvant CAPTEM is associated with favorable radiographic objective response rates for locally advanced or metastatic PNET and may facilitate selection of patients appropriate for surgical resection.

The functioning side of the pancreas: a review on insulinomas

PURPOSE

Insulinomas are a rare type of neuroendocrine tumors, originating in the pancreas, difficult to diagnose and to treat. Due to its rarity, insulinomas are a not well-known pathological entity; thus, the diagnostic process is frequently a medical challenge with many possible differential diagnoses. The diagnostic process varies between non-invasive procedures, such as the fasting test or imaging techniques, and invasive ones. Insulinomas are rarely malignant, but the glycemic imbalance correlated with this tumor can frequently alter the quality of life of the patients and the consequent hypoglycemia can be extremely dangerous. Moreover, insulinomas can be associated with different genetic syndromes, such as Multiple Endocrine Neoplasia 1, accompanied by other specific symptoms. There are many different treatment strategies, depending on the need to control symptoms or control diseases progression, the only curative one being surgery.

METHODS AND RESULTS

We reviewed the evidences present in the literature on insulinomas and reported its main clinical characteristics and management strategies.

CONCLUSION

The aim of this review of the literature is to present the current knowledge on insulinomas, exploring the main clinical characteristics, the diagnostic tools, and the therapeutic strategies.

Diagnostic Approaches to Neuroendocrine Neoplasms of Unknown Primary Site

Neuroendocrine neoplasms (NENs) arise from cells of neuronal and endocrine differentiation. While they are a rare entity, an increasing proportion of patients with NEN present with metastatic disease and no evident primary site using routine imaging or histopathology. NENs of unknown primary site have a poorer prognosis, often due to the challenge of selecting appropriate evidence-based management. We review the available literature and guidelines for the management of NENs of unknown primary site including clinical features, biochemical tests, histopathology, imaging, surgical exploration and localised and systemic treatments. We also discuss novel molecular techniques currently under investigation to aid primary site identification.

Combination of weekly streptozocin and oral S-1 treatment for patients of unresectable or metastatic pancreatic neuroendocrine neoplasms

BACKGROUND

Streptozocin (STZ) administration with or without other cytotoxic drugs remains a crucial chemotherapy for patients with advanced pancreatic neuroendocrine neoplasms (Pan-NENs). However, the therapeutic effects of combination treatment with weekly STZ and oral S-1 therapy (STS1) remain unknown. Therefore, the aim of this study was to evaluate the safety and clinical feasibility of STS1.

METHODS

Twenty of 243 Pan-NEN patients were included in this retrospective study, all of whom had received STS1 for unresectable or distant metastatic diseases from November 2015 to January 2019. The maximum tumor shrinkage rate, time course of the tumor shrinkage rate, prognosis (progression-free survival and overall survival), and adverse events were evaluated.

RESULTS

The median age of the patients was 61.5 years and the median tumor size was 35 mm. The number of NET-G1, NET-G2, NET-G3, and NEC-G3 patients was 3, 13, 3, and 1, respectively. The median Ki-67 index and mitoses were 10.2% and 2/10 high-power fields, respectively. The overall objective response rate and disease control rate were 30% and 90%, respectively. The median maximum tumor reduction rate was 19%. The Ki-67 index and tumor size did not influence the tumor shrinkage rate. Progression-free survival after STS1 treatment was 19 months with no significant difference between NET-G1/G2 and NET-G3/NEC-G3 patients (p = 0.4). There was one case each of grade 3/4 toxicity, including general fatigue, hyperglycemia, and renal dysfunction. No serious myelosuppressive events are manifested.

CONCLUSIONS

STS1 treatment is an effective and safe therapeutic option for patients with advanced Pan-NEN.

PRRT neuroendocrine tumor response monitored using circulating transcript analysis: the NETest

PURPOSE

Peptide receptor radionuclide therapy (PRRT) is effective for metastatic/inoperable neuroendocrine tumors (NETs). Imaging response assessment is usually efficient subsequent to treatment completion. Blood biomarkers such as PRRT Predictive Quotient (PPQ) and NETest are effective in real-time. PPQ predicts PRRT efficacy; NETest monitors disease. We prospectively evaluated: (1) NETest as a surrogate biomarker for RECIST; (2) the correlation of NETest levels with PPQ prediction.

METHODS

Three independent ¹⁷⁷Lu-PRRT-treated GEP-NET and lung cohorts (Meldola, Italy: n = 72; Bad-Berka, Germany: n = 44; Rotterdam, Netherlands: n = 41). Treatment response: RECIST1.1 (responder (stable, partial, and complete response) vs non-responder). Blood sampling: pre-PRRT, before each cycle and follow-up (2-12 months). PPQ (positive/negative) and NETest (0-100 score) by PCR. Stable < 40; progressive > 40). CgA (ELISA) as comparator. Samples de-identified, measurement and analyses blinded. Kaplan-Meier survival and standard statistics.

RESULTS

One hundred twenty-two of the 157 were evaluable. RECIST stabilization or response in 67%; 33% progressed. NETest significantly (p < 0.0001) decreased in RECIST "responders" (- 47 ± 3%); in "non-responders," it remained increased (+ 79 ± 19%) (p < 0.0005). NETest monitoring accuracy was 98% (119/122). Follow-up levels > 40 (progressive) vs stable (< 40) significantly correlated with mPFS (not reached vs. 10 months; HR 0.04 (95%CI, 0.02-0.07). PPQ response prediction was accurate in 118 (97%) with a 99% accurate positive and 93% accurate negative prediction. NETest significantly (p < 0.0001) decreased in PPQ-predicted responders (- 46 ± 3%) and remained elevated or increased in PPQ-predicted non-responders (+ 75 ± 19%). Follow-up NETest categories stable vs progressive significantly correlated with PPQ prediction and mPFS (not reached vs. 10 months; HR 0.06 (95%CI, 0.03-0.12). CgA did not reflect PRRT treatment: in RECIST responders decrease in 38% and in non-responders 56% (p = NS).

CONCLUSIONS

PPQ predicts PRRT response in 97%. NETest accurately monitors PRRT response and is an effective surrogate marker of PRRT radiological response. NETest decrease identified responders and correlated (> 97%) with the pretreatment PPQ response predictor. CgA was non-informative.

Trends in the Number of Lymph Nodes Evaluated Among Patients with Pancreatic Neuroendocrine Tumors in the United States: A Multi-Institutional and National Database Analysis

BACKGROUND

The role of routine lymphadenectomy in the surgical treatment of pancreatic neuroendocrine tumors (pNET) remains poorly defined. The objective of the current study was to investigate trends in the number of lymph nodes (LN) evaluated for pNET treatment at a nationwide level.

METHODS

Patients undergoing surgery for pNET between 2000 and 2016 were identified in the U.S. Neuroendocrine Tumor Study Group (US-NETSG) database as well as the Surveillance, Epidemiology, and End Results (SEER) database. The number of LNs examined was evaluated over time.

RESULTS

The median number of evaluated LNs increased roughly fourfold over the study period (US-NETSG, 2000: 3 LNs vs. 2016: 13 LNs; SEER, 2000: 3 LNs vs. 2016: 11 LNs, both p < 0.001). While no difference in 5-year OS and RFS was noted among patients who had 1-3 lymph node metastases (LNM) vs. ≥ 4 LNM between 2000-2007 (OS 73.5% vs. 69.9%, p = 0.12; RFS: 64.9% vs. 40.1%, p = 0.39), patients who underwent resection and LN evaluation during the period 2008-2016 had an incrementally worse survival if the patient had node negative disease, 1-3 LNM and ≥ 4 LNM (OS 86.8% vs. 82.7% vs. 74.9%, p < 0.001; RFS: 86.3% vs. 64.7% vs. 50.4%, p < 0.001). On multivariable analysis, a more recent year of diagnosis, pancreatic head tumor location, and tumor size > 2 cm were associated with 12 or more LNs evaluated in both US-NETSG and SEER databases.

CONCLUSION

The number of LNs examined nearly quadrupled over the last decade. The increased number of LNs examined suggested a growing adoption of the AJCC staging manual recommendations regarding LN evaluation in the treatment of pNET.

Treatment of Gastroenteropancreatic Neuroendocrine Tumors

Neuroendocrine tumors (NETs) represent a group of biologically and clinically heterogeneous neoplasms arising from the diffuse neuroendocrine system. Although NETs may develop in almost any organ, they commonly arise in the gastrointestinal tract and pancreas and are referred to as gastroenteropancreatic (GEP)-NETs when they arise from these sites. In recent years, advances in understanding of the biology of NETs have resulted in an expansion in treatment options and improved survival for patients. This review focuses on treatment of GEP-NETS and highlights factors that govern the therapeutic approach.

Systemic Therapies for Metastatic Pancreatic Neuroendocrine Tumors

OPINION STATEMENT

Over the years, there have been significant advances in systemic treatments for metastatic pancreatic neuroendocrine tumors (panNETs). Despite these advancements, uncertainty remains regarding how to best sequence available therapies. For well-differentiated and metastatic panNETs that are somatostatin receptor (SSTR) avid on functional imaging, first-line therapy typically consists of somatostatin analogs (SSAs), given their favorable toxicity profile and overall low burden for patients. When progression of disease is observed on an SSA, multiple treatment options are available, including the targeted agents everolimus and sunitinib, peptide receptor radionuclide therapy (PRRT), as well as chemotherapy, with the latter often preferred for those panNETs of heavy tumor burden, higher grade, and/or more aggressive behavior clinically and/or radiographically. Here, we review panNET classification, currently available systemic treatments, therapy sequencing, and areas of active investigation to further our treatments for the disease.

Pancreatic neuroendocrine tumors

PURPOSE OF REVIEW

Pancreatic neuroendocrine tumors (pNETs) are a rare, heterogeneous group of pancreatic neoplasms with a wide range of malignant potential. They may manifest as noninfiltrative, slow-growing tumors, locally invasive masses, or even swiftly metastasizing cancers.

RECENT FINDINGS

In recent years, because of the increasing amount of scientific literature available for pNETs, the classification, prognostic stratification criteria, and available consensus guidelines for diagnosis and therapy have been revised and updated.

SUMMARY

The vast majority of new pNET diagnoses consist of incidentally discovered lesions on cross-sectional imaging. The biologic behavior of pNETs is defined by the grade and stage of the tumor. Surgery is the only curative treatment and it, therefore, represents the first therapeutic choice for any localized pNET; however, recent evidence suggests that patients with small (<2 cm), nonfunctioning G1 tumors can be safely observed.An aggressive surgical approach towards liver metastases is recommended in selected cases, as well as liver-directed therapies for disease control. In the presence of unresectable progressive disease, somatostatin analogs, targeted therapies such as everolimus, peptide receptor radionuclide therapy, and systemic chemotherapy are all useful tools for prolonging survival.

Prognostic factors influencing survival in small bowel neuroendocrine tumor with liver metastases

BACKGROUND

Resection of liver metastasis in small bowel neuroendocrine tumors (SBNET) may improve survival, however, factors influencing prognosis are unclear. We evaluated how the extent of resection influences outcomes.

METHODS

Patients with SBNET with liver metastasis from 1990 to 2013 who underwent resection of the primary tumor were identified. Outcomes among patients undergoing complete resection (CR), partial resection (PR), or no resection (NR) of liver metastases with resection of the primary tumor only were compared.

RESULTS

One hundred eleven patients met the criteria. The median number of liver lesions was seven and median lesions resected was one. Fifty (45%) patients had NR, 41 (36.9%) underwent CR, and 20 (18.1%) underwent PR. The 5-year overall survival (OS) was 79.4% for NR, 84.7% for PR, and 100% for CR, demonstrating a trend that CR was best, followed by PR then NR (P = .02). 10-year OS showed no significant differences (72.7% NR; 84.7% PR; 82.5% CR; P = .10). Greater than 10 liver lesions (hazard ratio [HR] 3.6; P = 0.04) or receiving chemotherapy (HR 3.7; P = .03) were negative predictors of survival.

CONCLUSION

The extent of resection of liver disease in SBNET influenced survival at 5 years but not at 10 years. In addition, more than 10 liver lesions and chemotherapy were predictors of mortality.

Spotlight on telotristat ethyl for the treatment of carcinoid syndrome diarrhea: patient selection and reported outcomes

Neuroendocrine tumors (NETs) are rare cancers with an associated prolonged survival in some patients. A proportion of patients diagnosed with NETs will present with carcinoid syndrome symptoms, characterized by diarrhea, flushing and/or wheezing. This review summarizes the current treatment options for carcinoid syndrome, focusing on the latest novel treatment option, telotristat ethyl. In addition, information on patient-reported outcomes and impact of carcinoid syndrome on quality of life (QOL) and improvement of following treatment with telotristat ethyl are reviewed. This article also provides an overview of the current QOL questionnaires for patients with NETs and addresses unmet needs in this field of patient-reported outcomes.

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.

Insights into the biology and treatment strategies of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are the second most common primary pancreatic neoplasms after pancreatic ductal adenocarcinoma. PNETs present with widely various clinical manifestation and unfavorable survival rate. The recent advances in next generation sequencing have significantly increased our understanding of the molecular landscape of PNETs and help guide the development of targeted therapies. This review intends to outline a holistic picture of the tumors by discussing current understanding of clinical presentations, up-to-date treatment strategies, novel mouse models, and molecular biology of PNETs. Furthermore, we will provide insight into the future development of more effective targeted therapies that are necessary to manage PNETs.

Treatment Options for Pancreatic Neuroendocrine Tumors

The management of pancreatic neuroendocrine tumors (PanNETs) involves classification into non-functional or functional PanNET, and as localized or metastatic PanNET. In addition, while most PanNETs are sporadic, these endocrine neoplasms can also be manifestations of genetic syndromes. All these factors may assist in forming a risk stratification system permitting a tailored management approach. Most PanNETs are classified as non-functional because they are not associated with clinical sequelae of hormone excess. They are characterized by non-specific symptoms, such as abdominal pain or weight loss, resulting from mass effect related to the pancreatic tumor or secondary to distant metastases. Accurate staging of the disease is essential for determining the appropriate approach to therapy. As cure is only potentially possible with surgical resection of the tumor, it is recommended to remove all localized and limited metastatic disease. However, many patients present with metastatic and/or advanced local disease. In such instances, the goal of therapy is to control tumor growth and/or decrease tumor burden, lengthen survival, and palliate local symptoms and those of hormone excess. This typically requires a multimodal approach, including surgery, liver-directed treatment, and systemic medical therapy.

Recent Updates in the Management of Advanced Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (pNETs) are rare neoplasms arising from the pancreatic islet of Langerhans and can be functioning or non-functioning based on the clinical symptoms caused by hormonal secretions. PNETs are the second most common tumor of the pancreas and represent 1-2% of all pancreatic neoplasms. The incidence of pNETs appears to be rising and the prognosis seems to be improving, likely due to the improved treatment options. Recent updates of the World Health Organization classification and grading separate pNETs into 2 broad categories according to the histopathologic criteria, including the Ki-67 proliferative index and mitotic counts: well-differentiated NET and poorly-differentiated neuroendocrine carcinoma (NEC). The classification also incorporates a new subcategory of well-differentiated high-grade NEC (grade 3) to the well-differentiated NET category. This new classification algorithm aims to improve the prediction of the clinical outcomes and survival and help clinicians select better therapeutic strategies for patient care and management. The treatment of advanced or metastatic pNETs may include surgical resection, liver-directed therapies, and/or systemic treatments. In unresectable patients, the goals of these therapies are to palliate the tumor-related symptoms and prolong the lifespan. Systemic therapy consists of the following broad modalities: somatostatin analogues, molecular targeted therapy, systemic chemotherapy, and peptide receptor radionuclide therapy. In conclusion, pNETs are diagnosed increasingly throughout the world, usually with metastatic disease and requiring systemic therapy. Each patient should be evaluated thoroughly and discussed individually by a multidisciplinary and dedicated NET-expert team, which might consider all treatment options, including ongoing clinical trials before selecting the appropriate treatment sequence.

Peptide receptor radionuclide therapy with 177Lu-DOTA-TATE as a promising treatment of malignant insulinoma: a series of case reports and literature review

INTRODUCTION

Insulinomas are a rare type of pancreatic neuroendocrine tumours characterized by insulin hypersecretion. They are considered malignant when metastases are present. Traditional therapies often promote only temporarily symptomatic relief and may be associated with severe adverse effects. There is scarce experience in treating malignant insulinomas with peptide receptors radionuclide therapy (PRRNT).

PATIENTS AND METHODS

We describe PRRNT results in four patients with inoperable malignant insulinomas with poorly controllable hypoglycaemia. All patients received therapy with ¹⁷⁷Lu-DOTA-TATE after conventional therapies failed in controlling disease progression and symptoms. The activity administered per cycle was 4.8-7.4 GBq. The interval between cycles was 10-16 weeks. Haematology, liver and kidney function tests were performed before treatment initiation and 5 and 10 weeks after each cycle.

RESULTS

Patient 1 presented significant clinical benefit for 13 months after PRRNT, with imaging improvement. Patient 2 obtained reduction of the number and severity of hypoglycaemic episodes during 15 months after therapy. Patient 3 is asymptomatic since PRRNT first cycle performed 23 months ago and revealed significant imaging improvement. Patient 4 had resolution of hypoglycaemia only 3 days after PRRNT first cycle and today, 16 months after therapy, the disease seems to be in remission and the patient maintains euglycaemic state. PRRNT was well tolerated, with only hematologic grade 2 toxicity in patient 1 and mild kidney toxicity in patient 3.

CONCLUSIONS

After the start of ¹⁷⁷Lu-DOTA-TATE all patients achieved hypoglycaemia symptomatic control and had evident improvement of their quality of life. Three patients showed imagiological improvement suggesting reduced tumour load.

CAPTEM in Metastatic Well-Differentiated Intermediate to High Grade Neuroendocrine Tumors: A Single Centre Experience

INTRODUCTION

Capecitabine-temozolomide (CAPTEM) has significant activity in patients (pts) with metastatic low grade pancreatic neuroendocrine tumors (NETs). However, there is limited data regarding its activity in pts with metastatic well-differentiated intermediate and high grade pancreatic and nonpancreatic NETs. The objective of this study was to assess the functional imaging response, survival, and tolerability of CAPTEM in this population.

METHODS

A retrospective audit of pts with metastatic well-differentiated intermediate (WHO grade 2) or high grade (WHO grade 3) NETs treated at Peter MacCallum Cancer Centre between March 2013 and March 2017. Pts received capecitabine 750 mg/m2 orally twice daily (bd) from days1 to 14 and temozolomide 100 mg/m2 bd from days 10 to 14 every 28 days. Data regarding functional imaging response, progression-free and overall survival, and toxicities was collected.

RESULTS

Thirty-two pts received a median of 6 cycles (range: 2-16) of CAPTEM for grade 2 (n=21, 66%) or grade 3 (n=11, 34%), Ki67 <55% (n= 7, 21.9%) or Ki67 ≥55% (n= 4, 12.5 %) NET. Primary site included gastroenteropancreatic (n= 17, 53%), lung (n= 12, 37.5%), and unknown origin (n = 3, 9.4%). Twenty-two percent received CAPTEM as first-line therapy. After a median of 31 months of follow-up, the two-year overall survival (OS) was 42%, with a median OS of 24 months. There was a trend towards improved median progression-free survival (PFS) in pts with low grade 3 (Ki67<55%) versus high grade 3 (Ki67 ≥55%) NETs (15 vs 4 months, p= 0.11). Ten (31.3%) experienced grade 3/4 toxicity, with nausea (15.6%), thrombocytopaenia (12.5%), and fatigue (9.4%) the most common toxicities reported.

CONCLUSION

CAPTEM has significant activity in patients with metastatic grades 2 and 3 NETs with manageable toxicity. The PFS benefit observed in the grade 3 subgroup with Ki67<55% warrants further evaluation in a larger randomized trial.

Current Treatment Options in Gastroenteropancreatic Neuroendocrine Carcinoma

Poorly differentiated gastroenteropancreatic neuroendocrine carcinomas (GEPNECs) are a rare neoplasm with a bleak prognosis. Currently there are little prospective data available for optimal treatment. This review discusses the current available regimens and the future direction for the treatment of GEPNECs. Treatment plans for GEPNECs are often adapted from those devised for small cell lung cancer; however, differences in these malignancies exist, and GEPNECs require their own treatment paradigms. As such, current first-line treatment for GEPNECs is platinum-based chemotherapy with etoposide. Studies show that response rate and overall survival remain comparable between cisplatin and carboplatin versus etoposide and irinotecan; however, prognosis remains poor, and more efficacious therapy is needed to treat this malignancy. Additional first-line and second-line treatment options beyond platinum-based chemotherapy have also been investigated and may offer further treatment options, but again with suboptimal outcomes. Recent U.S. Food and Drug Administration approval of peptide receptor radionuclide therapy in low- and intermediate-grade neuroendocrine tumors may open the door for further research in its usefulness in GEPNECs. Additionally, the availability of checkpoint inhibitors lends promise to the treatment of GEPNECs. This review highlights the lack of large, prospective studies that focus on the treatment of GEPNECs. There is a need for randomized control trials to elucidate optimal treatment regimens specific to this malignancy. IMPLICATIONS FOR PRACTICE: There are limited data available for the treatment of poorly differentiated gastroenteropancreatic neuroendocrine carcinomas (GEPNECs) because of the rarity of this malignancy. Much of the treatment regimens used in practice today come from research in small cell lung cancer. Given the poor prognosis of GEPNECs, it is necessary to have treatment paradigms specific to this malignancy. The aim of this literature review is to summarize the available first- and second-line GEPNEC therapy, outline future treatments, and highlight the vast gap in the literature.

Ameliorative and protective effects of ginger and its main constituents against natural, chemical and radiation-induced toxicities: A comprehensive review

Fatal unintentional poisoning is widespread upon human exposure to toxic agents such as pesticides, heavy metals, environmental pollutants, bacterial and fungal toxins or even some medications and cosmetic products. In this regards, the application of the natural dietary agents as antidotes has engrossed a substantial attention. One of the ancient known traditional medicines and spices with an arsenal of metabolites of several reported health benefits is ginger. This extended literature review serves to demonstrate the protective effects and mechanisms of ginger and its phytochemicals against natural, chemical and radiation-induced toxicities. Collected data obtained from the in-vivo and in-vitro experimental studies in this overview detail the designation of the protective effects to ginger's antioxidant, anti-inflammatory, and anti-apoptotic properties. Ginger's armoury of phytochemicals exerted its protective function via different mechanisms and cell signalling pathways, including Nrf2/ARE, MAPK, NF-ƙB, Wnt/β-catenin, TGF-β1/Smad3, and ERK/CREB. The outcomes of this review could encourage further clinical trials of ginger applications in radiotherapy and chemotherapy regime for cancer treatments or its implementation to counteract the chemical toxicity induced by industrial pollutants, alcohol, smoking or administered drugs.

Current best practice in the management of neuroendocrine tumors

Neuroendocrine neoplasms are rare tumors that display marked heterogeneity with varying natural history, biological behavior, response to therapy and prognosis. Their management is complex, particularly as a number of them may be associated with a secretory syndrome and involve a variety of options. A number of factors such as proliferation rate, degree of differentiation, functionality and extent of the disease are mostly utilized to tailor treatment accordingly, ideally in the context of a multidisciplinary team. In addition, a number of relevant scientific societies have published therapeutic guidelines in an attempt to direct and promote evidence-based treatment. Surgery remains the treatment of choice with an intention to cure while it may also be recommended in some cases of metastatic disease and difficult to control secretory syndromes. Long-acting somatostatin analogs constitute the main treatment for the majority of functioning tumors, whereas specific evolving agents such as telotristat may be used for the control of carcinoid syndrome and related sequelae. In patients with advanced disease not amenable to surgical resection, treatment options include locoregional therapies, long-acting somatostatin analogs, molecular targeted agents, radionuclides, chemotherapy and recently immunotherapy, alone or in combination. However, the ideal time of treatment initiation, sequence of administration of different therapies and identification of robust prognostic markers to select the most appropriate treatment for each individual patient still need to be defined.

Xylan-Based Hydrogels as a Potential Carrier for Drug Delivery: Effect of Pore-Forming Agents

Pore-forming agents have a significant influence on the pore structure of hydrogels. In this study, a porogenic technique was employed to investigate the preparation of macroporous hydrogels which were synthesized by radical copolymerization of carboxymethyl xylan with acrylamide and N-isopropylacrylamide under the function of a cross-linking agent. Six kinds of pore-forming agents were used: polyvinylpyrrolidone K30, polyethylene glycol 2000, carbamide, NaCl, CaCO₃, and NaHCO₃. The application of these hydrogels is also discussed. The results show that pore-forming agents had an important impact on the pore structure of the hydrogels and consequently affected properties of the hydrogels such as swelling ratio and mechanical strength, while little effect was noted on the thermal property of the hydrogels. 5-Fluorouracil was used as a model drug to study the drug release of the as-prepared hydrogels, and it was found that the drug release was substantially improved after using the NaHCO₃ pore-forming agent: a cumulative release rate of up to 71.05% was achieved.

My burning issues in neuroendocrine tumours (NET)

Several compounds have recently been approved for the systemic treatment of advanced well-differentiated neuroendocrine tumours (NET) of gastroenteropancreatic (GEP) or lung origin. Based on the PROMID and CLARINET trials, somatostatin analogues (SSA) are the preferred first-line approach for all GEP-NET and offer-in addition to antiproliferative effects-durable symptomatic relief for hormonally active tumours. The mTOR inhibitor everolimus has been approved for progressive GEP- and lung-NET and is a widely used drug in this setting. Furthermore, recent results have underlined the high efficacy of somatostatin-receptor targeting radionuclide therapy (PRRT) in somatostatin-receptor positive midgut tumours and PRRT is now considered standard treatment for midgut-NET progressing on SSA. The optimal application of PRRT in somatostatin receptor positive NET with non-midgut site is currently an issue of discussion and should be decided on an individually basis in multidisciplinary boards. Following new insights in the genetic landscape of NET, "hot topics" in recent months include optimal treatment of the recently defined NET G3 and preliminary data on immunotherapy.

Gastroenteropancreatic Neuroendocrine Tumors

Neuroendocrine tumors (NETs) are heterogeneous malignancies arising from the diffuse neuroendocrine system. They frequently originate in the gastroenteropancreatic (GEP) tract and the bronchopulmonary tree, and their incidence has steadily increased in the last 3 decades. Fundamental biologic and genomic differences underlie the clinical heterogeneity of NETs, and distinct molecular features characterize NETs of different grades and different primary sites. Although surgery remains the cornerstone of treatment for localized tumors, systemic treatment options for patients with metastatic NETs have expanded considerably. Somatostatin analogs have demonstrated both antisecretory and antitumor efficacy. Peptide receptor radionuclide therapy with lutetium-177 dotatate (¹⁷⁷ Lu-DOTATATE) has been approved for advanced GEP-NETs. The antitumor activity of everolimus has been demonstrated across a wide spectrum of NETs, and the antiangiogenic agent sunitinib has been approved for pancreatic NETs (pNETs). Chemotherapy with temozolomide and capecitabine has recently demonstrated an unprecedented prolongation of progression-free survival in a randomized trial of pNETs. Multiple retrospective series have reported the efficacy of liver-directed therapies both for palliating symptoms of hormone excess and for controlling tumor growth. Telotristat, an oral inhibitor of tryptophan hydroxylase, has been shown to reduce diarrhea in patients with carcinoid syndrome. Defining the therapeutic algorithm and identifying biomarkers predictive of response to treatments are among the main priorities for the next decade of research in the NET field.

Safety and efficacy of combining capecitabine and temozolomide (CAPTEM) to treat advanced neuroendocrine neoplasms: A meta-analysis

Retrospective studies have suggested that capecitabine combined with temozolomide (CAPTEM) is effective for treating patients with advanced neuroendocrine neoplasms (NENs); however, the efficacy and safety of this regimen needs to be verified by high-quality evidence or results of randomized controlled trials.We carried out a meta-analysis to evaluate the safety and effectiveness of a CAPTEM protocol for patients with advanced NENs. Systematic electronic literature searches were conducted using PubMed, EMBASE, and the Cochrane Library, and among meeting abstracts of the American Society of Clinical Oncology, European Society for Medical Oncology, European Neuroendocrine Tumor Society, and North American Neuroendocrine Tumor Society, up to June 30, 2017. We selected studies describing CAPTEM regimens for treating advanced NENs and reported on tumor response and/or toxicities according to clear World Health Organization (WHO) grading of patients. Three reviewers independently and repeatedly identified studies, extracted data, and assessed the quality of the literature. A single-proportion meta-analysis was applied to included articles.Fifteen studies with a total of 384 individuals were included. Medium overall survival in most studies was more than 12 months, whereas medium progression-free survival was similar or slightly higher than that in studies using other treatment regimes. Disease control rate of CAPTEM administration for patients with NENs was 72.89% (95% confidence interval, 64.04-81.73%; I = 82.4%; P < .01). WHO grade 3 to 4 toxicities, such as thrombocytopenia (3.36%), neutropenia (0.69%), lymphopenia (0.65%), anemia (0.59%), mucositis (0.57%), fatigue (0.54%), diarrhea (0.49%), nausea (0.39%), and transaminase elevation (0.13%) were reported in the trials included.CAPTEM is effective and relatively safe for treating patients with advanced NENs.

The Genesis of the Neuroendocrine Tumors Concept: From Oberndorfer to 2018

The concept of neuroendocrine tumors (NETs) began in the 1900s with Oberndorfer's description of carcinoid tumors, followed by specific cytotoxic agents and the identification of somatostatin. NETs diagnosis was confirmed by World Health Organization classification. Histopathology included immunohistochemistry with specific antibodies. Imaging was refined with molecular imaging. Somatostatin is the leading agent for controlling clinical symptoms related to hormone production. Increasing interest in these tumors, previously thought rare, led to increased incidence and prevalence. Between 1960 and 1970, the true NET-concept was established with development of radioimmunoassays for peptides and hormones, and imaging with computerized tomography.

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.

Biology and Systemic Treatment of Advanced Gastroenteropancreatic Neuroendocrine Tumors

In recent years, there have been important scientific advances in the biologic characterization of neuroendocrine neoplasms and in their treatment. This review will describe these scientific advances, the evolving systemic treatment approaches, and important topics to be addressed in future research.

The Role of Cytotoxic Chemotherapy in Advanced Pancreatic Neuroendocrine Tumors

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are rare neoplasms accounting for less than 5% of all pancreatic malignancies. These tumors are characterized by clinical and prognostical heterogeneity and are predominantly diagnosed in a metastatic stage. Cytotoxic chemotherapy, along with alkylating agents and antimetabolites as well as molecular targeted agents (everolimus, sunitinib), is used in the treatment of advanced PNETs. After the approval of lanreotide for unresectable PNETs, an additional therapeutic option has become available; however, the best sequence of therapies and patient stratification to different treatments remains challenging. Furthermore, no randomized phase-3 trials or head-to-head comparisons are available to support treatment decisions.

SUMMARY

The publication of 3 large single-center retrospective studies on streptozocin-(STZ)-based chemotherapy in advanced PNETs in 2015 confirmed the effectiveness of this treatment as described in previously reported trials. All studies investigated markers for progression-free and overall survival and strongly supported the value of the Ki-67 index as a robust prognostic marker. Interestingly, chemotherapy consistently displayed antitumor efficacy in different therapeutic lines. Moreover, a recent study of dacarbazine (DTIC) in a cohort of patients predominantly with PNETs demonstrated that a once monthly infusional DTIC schedule was well tolerated and yielded similar response rates (RR) as STZ-based schedules. Given the overall good tolerability of a monthly infusion and RR similar to STZ schedules, DTIC thus represents a feasible alternative or additional treatment option for PNETs. In this article, we review the current standard and summarize the most recent advances in the field of cytotoxic chemotherapy for PNET patients. Key Messages: (1) Despite the lack of phase3 trials, cytotoxic chemotherapy offers efficacy for patients with advanced PNETs; (2) the best therapeutic option and sequence remain open since comparable randomized studies are lacking; (3) careful patient selection and treatment stratification may increase overall outcome; and (4) currently, no biomarkers for clinical routine exist to predict response to chemotherapy.

Capecitabine and Temozolomide in Neuroendocrine Tumor of Unknown Primary

Incidence of low grade well-differentiated neuroendocrine tumors (NET) is on the rise. The North American Neuroendocrine Tumor Society estimates that the United States has more than 150,000 gastroenteropancreatic NET patients. About 10% of metastatic NETs can be unknown primary, and due to their rarity, dedicated treatment algorithms and regimens are not defined. Combination of capecitabine and temozolomide (CAPTEM) is one of the systemic treatments used in gastroenteropancreatic NETs. We explored clinical activity of CAPTEM in NET of unknown primary. Methods. Retrospective review of NET of unknown primary managed at the University of Kentucky over the past five years (2012–2016). Result. 56 patients with NET of unknown primary were identified; 12 patients were treated with CAPTEM. Median progression-free survival on CAPTEM in grade II and grade III NET of unknown primary was 10.8 and 7 months, respectively. Six patients showed reduction in metastatic tumor volume at three-month CT scan. Three patients had stable disease and three patients showed disease progression at the first surveillance scan. Common side-effects were as follows: four patients developed grade II thrombocytopenia, three patients developed grade I lymphocytopenia, and two patients developed hand foot syndrome (grades I and III). Six patients developed grade I fatigue. Conclusion. CAPTEM should be considered for grades I and II NET of unknown primary, especially in the case of visceral crisis or bulky disease.

Preoperative Fluorouracil, Doxorubicin, and Streptozocin for the Treatment of Pancreatic Neuroendocrine Liver Metastases

INTRODUCTION

While preoperative chemotherapy is frequently utilized before resection of non-neuroendocrine liver metastases, patients with resectable neuroendocrine liver metastases typically undergo surgery first. FAS is a cytotoxic chemotherapy regimen that is associated with substantial response rates in locally advanced and metastatic pancreatic neuroendocrine tumors.

METHODS

All patients who underwent R0/R1 resection of pancreatic neuroendocrine liver metastases at a single institution between 1998 and 2015 were included. The outcomes of patients treated with preoperative FAS were compared with those of patients who were not.

RESULTS

Of the 67 patients included, 27 (40.3%) received preoperative FAS, whereas 40 (59.7%) did not. Despite being associated with higher rates of synchronous disease, lymph node metastases, and larger tumor size, patients who received preoperative FAS had similar overall survival [overall survival (OS), 108.2 months (95% confidence interval (CI) 78.0-136.0) vs. 107.0 months (95% CI 78.0-136.0), p = 0.64] and recurrence-free survival [RFS, 25.1 months (95% CI 23.2-27.0) vs. 18.0 months (95% CI 13.8-22.2), p = 0.16] as patients who did not. Among patients who presented with synchronous liver metastases (n = 46), the median OS [97.3 months (95% CI 65.9-128.6) vs. 65.0 months (95% CI 28.1-101.9), p = 0.001] and RFS [24.8 months (95% CI 22.6-26.9) vs. 12.1 months (2.2-22.0), p = 0.003] were significantly greater among patients who received preoperative FAS compared with those who did not.

CONCLUSIONS

The use of FAS before liver resection is associated with improved OS compared with surgery alone among patients with advanced synchronous pancreatic neuroendocrine liver metastases.

Current and emerging therapies for PNETs in patients with or without MEN1

Pancreatic neuroendocrine tumours (PNETs) might occur as a non-familial isolated endocrinopathy or as part of a complex hereditary syndrome, such as multiple endocrine neoplasia type 1 (MEN1). MEN1 is an autosomal dominant disorder characterized by the combined occurrence of PNETs with tumours of the parathyroids and anterior pituitary. Treatments for primary PNETs include surgery. Treatments for non-resectable PNETs and metastases include biotherapy (for example, somatostatin analogues, inhibitors of receptors and monoclonal antibodies), chemotherapy and radiological therapy. All these treatments are effective for PNETs in patients without MEN1; however, there is a scarcity of clinical trials reporting the efficacy of the same treatments of PNETs in patients with MEN1. Treatment of PNETs in patients with MEN1 is challenging owing to the concomitant development of other tumours, which might have metastasized. In recent years, preclinical studies have identified potential new therapeutic targets for treating MEN1-associated neuroendocrine tumours (including PNETs), and these include epigenetic modification, the β-catenin-wingless (WNT) pathway, Hedgehog signalling, somatostatin receptors and MEN1 gene replacement therapy. This Review discusses these advances.

Management of functional neuroendocrine tumors of the pancreas

Pancreatic neuroendocrine tumors (pNETs) constitute a heterogenous group of malignancies with varying clinical presentation, tumor biology and prognosis. The incidence of pNETs has steadily increased during the last decades with an estimated incidence 2012 of 4.8/100,000. Recent whole genome sequencing of pNETs has demonstrated mutations in the DNA repair genes MUTYH and point mutations and gene fusions in four main pathways from chromatin remodeling, DNA damage repair, activation of mechanistic target of rapamycin (mTOR) signaling and the telomere maintenance. This new information will be the foundation for new therapies in the near future for malignant pNETs. The functioning pNETs constitute about 30-40% of all pNETs displaying nine different clinical syndromes: insulinoma, Zollinger-Ellison, Verner-Morrison, glucagonoma, somatostatinomas, ectopic adrenocorticotropic hormone (ACTH) and parathyroid hormone related peptide (PTH-rP) syndromes. Single patients might also present carcinoid syndrome. The diagnostic work-up include histopathology with the new WHO 2017 Classification, biomarkers (CgA, NSE), radiology and molecular imaging including CT-scan, magnetic resonance imaging (MRI), ultrasound and PET-scan. A cornerstone in the treatment of pNETs is surgery which is rarely curative but can reduce the clinical symptoms by debulking which also include radiofrequency ablation, embolization of liver metastases. Medical treatment includes chemotherapy and the targeted agents such as everolimus, sunitinib and peptide receptor radiotherapy (PRRT). Somatostatin analogs has for the last decades been the main stay for management for clinical symptoms related to functioning pNETs and is often combined with new targeted agents as well as chemotherapy. Long-term management of functioning pNETs need a combination of different procedures, surgery, local ablation, targeted agents and somatostatin analogs. Future therapies might be based on the recent advances in molecular genetics and tumor biology.

Outcomes and toxicity following Yttrium-90 radioembolization for hepatic metastases from neuroendocrine tumors-a single-institution experience

Background

The prognosis of patients with hepatic metastases from neuroendocrine tumors (NET) is generally good, and radioembolization with Yttrium-90 microspheres is a locoregional therapy that is used in efforts to improve hepatic disease control and survival. This study aims to describe the survival outcomes and toxicities associated with radioembolization for hepatic-predominant metastatic NET in a large single-institution cohort.

Methods

A total of 59 patients underwent radioembolization for metastatic NET with hepatic predominant disease at a single academic center. Patient outcomes were analyzed by Kaplan-Meier survival analysis and toxicities were detailed and described. Ten patients within the cohort underwent post-treatment dosimetric analysis using PET-MRI and normal liver dosimetry was correlated with hepatic fibrosis and toxicity.

Results

Median overall survival from time of radioembolization in the patient cohort was 31 months, and the 1- and 2-year overall survival was 80.4% and 65.6% respectively. Median hepatic progression-free survival and overall progression-free survival were 18 and 13 months, respectively. Three patients died of hepatic failure that was possibly therapy-related. Ten patients underwent evaluation of post-treatment dosimetry following radioembolization. In patients who did not develop hepatotoxicity or hepatic fibrosis, mean dose to normal liver was 25.4 Gy, while the mean liver dose in patients who experienced toxicity (hepatic fibrosis in n=2 and death from hepatic failure in n=1) was 59.1 Gy.

Conclusions

Overall survival following radioembolization for hepatic metastases from NET is excellent; however, deaths that are potentially treatment-related have been observed. Preliminary data regarding dose to normal liver is suggestive of a relation between dosimetry and toxicity, however further work is required to further elucidate the mechanism, correlation with dosimetry, as well as additional patient and tumor factors that may predispose these patients to toxicity.

Aggressive neuroendocrine tumor of the ovary with multiple metastases treated with everolimus: A case report

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Neuroendocrine tumors (NETs) frequently occur in the lungs or the gastrointestinal tract; they are uncommon in the ovary.

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The mammalian target of rapamycin (mTOR) pathway has been reported as a treatment for advanced NETs.

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We describe a patient with an aggressive primary ovarian NET, successfully treated with everolimus (an mTOR inhibitor).

Chromogranin A as circulating marker for diagnosis and management of neuroendocrine neoplasms: more flaws than fame

Owing to the heterogeneity of neuroendocrine neoplasms (NENs), the availability of reliable circulating markers is critical for improving diagnostics, prognostic stratification, follow-up and definition of treatment strategy. This review is focused on chromogranin A (CgA), a hydrophilic glycoprotein present in large dense core vesicles of neuroendocrine cells. Despite being long identified as the most useful NEN-related circulating marker, clinical application of CgA is controversial. CgA assays still lack standardization, thus hampering not only clinical management but also the comparison between different analyses. In the diagnostic setting, clinical utility of CgA is limited as hampered by (a) the variety of oncological and non-oncological conditions affecting marker levels, which impairs specificity; (b) the fact that 30-50% of NENs show normal CgA, which impairs sensitivity. Regarding the prognostic phase, there is prospective evidence which demonstrates that advanced NENs secreting CgA have poorer outcome, as compared with those showing non-elevated marker levels. Although the identification of cut-offs allowing a proper risk stratification of CgA-secreting patients has not been performed, this represents the most important clinical application of the marker. By contrast, based on prospective studies, the trend of elevated circulating CgA does not represent a valid indicator of morphological evolution and has therefore no utility for the follow-up phase. Ultimately, current knowledge about the role of the marker for the definition of treatment strategy is poor and is limited by the small number of available studies, their prevalent retrospective nature and the absence of control groups of untreated subjects.

Chemotherapy in NETs: When and how

The majority of neuroendocrine tumours (NETs) are well-differentiated tumours that follow an indolent course, in contrast to a minority of poorly differentiated neuroendocrine carcinomas (NECs) which exhibit an aggressive course and assocaited with an overall short survival. Although surgery is the only curative treatment for NETs it is not always feasible,necessitating the application of other therapies including chemotherapy. Streptozotocin (STZ)-based regimens have long been used for advanced or metastatic well-to-moderately differentiated (G1-G2) NETs, especially those originating from the pancreas (pNETs). In poorly differentiated grade 3 (G3) tumours, platinum-based chemotherapy is recommended as first-line therapy, albeit without durable responses. Although data for temozolomide (TMZ)-based chemotherapy are still evolving, this treatment may replace STZ-based regimens in pNETs due to its better tolerability and side effect profile. In addition, there is evidence that TMZ could also be used in the subgroup of well-differentiated G3 NETs. There is less clear-cut evidence of a benefit for chemotherapy in intestinal NETs, but still evolving data suggest that TMZ may be efficacious in particular patients. In lung and thymic carcinoids, chemotherapy is reserved for patients with progressive metastatic disease in whom other treatment options are unavailable. Overall, chemotherapy is indicated in patients who have progressed on first-line treatment with somatostatin analogues, have extensive tumour load or exhibit rapid growth following a period of follow-up, and/or have a high proliferative rate; it may occasionally can be used in a neo-adjuvant setting. Prospective randomised studies are awaited to substantiate the role of chemotherapy in the therapeutic algorithm of NETs along with other evolving treatments.

Nothing But NET: A Review of Neuroendocrine Tumors and Carcinomas

This review covers the diverse topic of neuroendocrine neoplasms (NENs), a relatively rare and heterogeneous tumor type, comprising ~2% of all malignancies, with a prevalence of <200,000 in the United States, which makes it an orphan disease (Basu et al., 2010).1 For functional purposes, NENs are divided into two groups on the basis of clinical behavior, histology, and proliferation rate: well differentiated (low grade to intermediate grade) neuroendocrine tumors and poorly differentiated (high grade) neuroendocrine carcinoma (Bosman et al., 2010)2; this histological categorization/dichotomization is highly clinically relevant with respect to impact on treatment and prognosis even though it is not absolute since a subset of tumors with a low-grade appearance behaves similarly to high-grade lesions. Given the relative dearth of evidenced-based literature about this orphan disease as a whole (Modlin et al., 2008),3 since the focus of most articles is on particular anatomic subtypes of NENs (i.e., gastroenteropancreatic or pulmonary), the purpose of this review is to summarize the presentation, pathophysiology, staging, current standard of care treatments, and active areas of current research.