Streptozocin and 5-Fluorouracil for the Treatment of Pancreatic Neuroendocrine Tumors: Efficacy, Prognostic Factors and Toxicity

Systemic Therapy for Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PanNETs) account for approximately 2% of all pancreatic malignancies. Several systemic treatment options have been developed over the last four decades, ranging from cytotoxic chemotherapy and octreotide to newer targeted therapies like sunitinib, cabozantinib, and lenvatinib. Although surgery or liver-directed therapy remains cornerstone for management of metastatic PanNETs, however, they remain unfeasible in majority of cases. PanNETs behave differently than SI-NETs (small intestinal NET); the former is more aggressive and less responsive to somatostatin-based therapies. The optimal sequence of the systemic therapies for the advanced PanNETs depends mainly on the tumor burden, Ki-67 index, and the tempo of the disease. In the end, drawing from ENETS (European Neuroendocrine Tumor Society) and ESMO (European Society for Medical Oncology) guidelines, we propose a working algorithm for the management of advanced PanNETs, not amenable to surgery or liver-directed therapies.

Predictive Factors of Response to Streptozotocin in Neuroendocrine Pancreatic Neoplasms

Pancreatic neuroendocrine neoplasms (Pan-NENs) may exhibit a heterogeneous clinical course, ranging from indolent to progressive/metastatic behavior. In the latter scenario, streptozocin (STZ) is considered the cornerstone of systemic treatment; however, response to STZ-based chemotherapy may vary among individuals. In this narrative review, we aimed to identify the predictive factors of response to STZ in advanced Pan-NENs. We performed an extensive search in international online databases for published studies and ongoing clinical trials evaluating STZ in Pan-NENs. We found 11 pertinent studies evaluating 17 patient-, tumor-, or treatment-related factors. Age, CgA blood levels, tumor grade, Ki-67% index, anatomical location of the primary tumor, tumor stage, site of metastasis origin, liver tumor burden, extrahepatic spread, functional status, O6-methylguanine-methyltransferase (MGMT) status, line of therapy, and response to previous treatments were all statistically associated with radiological response and/or survival. The identified predictors may help clinicians make appropriate treatment decisions, in this way improving clinical outcomes in patients with advanced Pan-NENs.

[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.

SEOM-GETNE clinical guidelines for the diagnosis and treatment of gastroenteropancreatic and bronchial neuroendocrine neoplasms (NENs) (2022)

Neuroendocrine neoplasms (NENs) are a heterogeneous family of tumors of challenging diagnosis and clinical management. Their incidence and prevalence continue to rise mainly due to an improvement on diagnostic techniques and awareness. Earlier detection, along with steadfast improvements in therapy, has led to better prognosis over time for advanced gastrointestinal and pancreatic neuroendocrine tumors. The aim of this guideline is to update evidence-based recommendations for the diagnosis and treatment of gastroenteropancreatic and lung NENs. Diagnostic procedures, histological classification, and therapeutic options, including surgery, liver-directed therapy, peptide receptor radionuclide therapy, and systemic hormonal, cytotoxic or targeted therapy, are reviewed and discussed, and treatment algorithms to guide therapeutic decisions are provided.

What have we learnt from the past - would treatment decisions for GEP-NET patients differ between 2012 to 2016 by the new recommendations in 2022?

BACKGROUND

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of tumors with a broad range of local and systemic treatment options. Still a lack of data regarding treatment sequences exists. The aim of this study was to analyse outcomes in GEP-NETs depending on stage and treatment steps and compare our treatment decisions to the latest treatment recommendations of European Society of Medical Oncology (ESMO) 2020 for GEP-NETs.

METHODS

Patients were included in this retrospective single-center analysis from 2012-2016. All patients suffering from a GEP-NET, who were screened, treated or evaluated at ENETS Center in Zurich, Switzerland were included in analysis. Patients with any other diagnosis of NET were not included. We used Kaplan Meier estimator as well as Cox regression to compare survival rates between different sites of localization, grades or stages and treatment sequences.

RESULTS

Overall, we identified 256 GEP-NETs, most in advanced stage (62%) and located in small intestine tract or pancreatic gland. Survival depended on stage, grade, primary site and duration of response for the early systemic treatment. On average patients underwent 2.6 different treatment modalities, mostly depending on stage and higher tumor grade. Surgery was performed early but also in advanced stages, usually followed by Somatostatine-Agonist modalities. In distant disease (Stage IV), we investigated a positive effect of PFS after treatment with Somatostatine Analogues (SSA) (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.21 - 0.97; p = 0.04) and systemic treatment (HR, 0.51; 95% CI, 0.26 - 0.99; p = 0.047) if patients underwent prior surgery or endoscopic resection. Kaplan Meier distributions predict shorter OS in distant disease (Stage IV), (Figure. 1; HR, 2.06; 95% CI, 1.46 - 2.89; log-rank test, p < 0.001).

CONCLUSION

This retrospective analysis presents a great overview of all patients', disease and treatment characteristics of GEP-NETs at ENETS Center in Zurich, Switzerland. We illustrated survival (PFS) depending on implemented therapies. According to these findings, we formed a suggested treatment algorithm for advanced GEP-NETs, which does not differ from the latest treatment recommendation by ESMO guidelines for GEP-NETs. The results of this project may define GEP-NET patients' selection for upcoming clinical prospective studies.

Capecitabine and temozolomide for metastatic intermediate to high-grade pancreatic neuroendocrine neoplasm: a single center experience

BACKGROUND/AIMS

The combination of capecitabine and temozolomide (CAPTEM) is one of the treatment options for metastatic pancreatic neuroendocrine neoplasms (pNENs). This study aims to evaluate the efficacy of CAPTEM in patients with metastatic intermediate to high-grade pancreatic neuroendocrine tumor (pNET) or carcinoma (pNEC).

METHODS

This study was conducted retrospectively in a single center. Patients were treated for intermediate to high-grade tumor with 750 mg/m² of capecitabine twice daily from day 1 to 14 and 200 mg/m² of temozolomide once daily from day 10 to 14, repeating twice in a cycle of 28 days. The primary outcomes were durations of overall survival (OS) and progression-free survival (PFS). The secondary outcomes consisted of objective response rate and disease control rate.

RESULTS

A total of 12 patients (grade 2 NET in six, grade 3 NET in three, NEC in three patients) who received CAPTEM were included in this study. Patients received a median of five cycles (range, 2 to 46) of CAPTEM. The median dose combined 1,150 mg of capecitabine and 300 mg of temozolomide. The median OS and PFS were 41.2 months (range, 3.2 to 167) and 39.7 months (range, 2.1 to 100), respectively. Patients with NET had longer OS and PFS compared to those of patients with NEC (p = 0.002 and p = 0.028). High Ki-67 proliferative index (&gt; 50%) was significantly associated with poor survival outcomes.

CONCLUSION

CAPTEM showed favorable survival outcomes in patients with metastatic intermediate to high-grade pNENs. Our study supports that CAPTEM may be an effective treatment option for metastatic pNENs.

Novel therapeutic approaches in GEP-NETs based on genetic and epigenetic alterations

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are heterogeneous malignancies with distinct prognosis based on primary tumor localization, grade, stage and functionality. Surgery remains the only curative option in localized tumors, but systemic therapy is the mainstay of treatment for patients with advanced disease. For decades, the therapeutic landscape of GEP-NETs was limited to chemotherapy regimens with low response rates. The arrival of novel agents such as somatostatin analogues, peptide receptor radionuclide therapy, tyrosine kinase inhibitors or mTOR-targeted drugs, has changed the therapeutic paradigm of GEP-NETs. However, the efficacy of these agents is limited in time and there is scarce knowledge of optimal treatment sequencing. In recent years, massive parallel sequencing techniques have started to unravel the genomic intricacies of these tumors, allowing us to better understand the mechanisms of resistance to current treatments and to develop new targeted agents that will hopefully start an era for personalized treatment in NETs. In this review we aim to summarize the most relevant genomic aberrations and signaling pathways underlying GEP-NET tumorigenesis and potential therapeutic strategies derived from them.

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

Simple Summary

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

Abstract

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

Predictive Factors for Resistant Disease with Medical/Radiologic/Liver-Directed Anti-Tumor Treatments in Patients with Advanced Pancreatic Neuroendocrine Neoplasms: Recent Advances and Controversies

Simple Summary

Tumor resistance, both primary and acquired, is leading to increased complexity in the nonsurgical treatment of patients with advanced panNENs, which would be greatly helped by reliable prognostic/predictive factors. The importance in identifying resistance is being contributed to by the increased array of possible treatments available for treating resistant advanced disease; the variable clinical course as well as response to any given treatment approach of patients within one staging or grading system, the advances in imaging which are providing increasing promising results/parameters that correlate with grading/outcome/resistance, the increased understanding of the molecular pathogenesis providing promising prognostic markers, all of which can contribute to selecting the best treatment to overcome resistance disease. Several factors have been identified that have prognostic/predictive value for identifying development resistant disease and affecting overall survival (OS)/PFS with various nonsurgical treatments of patients with advanced panNENs. Prognostic factors identified for patients with advanced panNENs for both OS/PFSs include various clinically-related factors (clinical, laboratory/biological markers, imaging, treatment-related factors), pathological factors (histological, classification, grading) and molecular factors. Particularly important prognostic factors for the different treatment modalities studies are the recent grading systems. Most prognostic factors for each treatment modality for OS/PFS are not specific for a given treatment option. These advances have generated several controversies and new unanswered questions, particularly those related to their possible role in predicting the possible sequence of different anti-tumor treatments in patients with different presentations. Each of these areas is reviewed in this paper.

Abstract

Purpose: Recent advances in the diagnosis, management and nonsurgical treatment of patients with advanced pancreatic neuroendocrine neoplasms (panNENs) have led to an emerging need for sensitive and useful prognostic factors for predicting responses/survival. Areas covered: The predictive value of a number of reported prognostic factors including clinically-related factors (clinical/laboratory/imaging/treatment-related factors), pathological factors (histological/classification/grading), and molecular factors, on therapeutic outcomes of anti-tumor medical therapies with molecular targeting agents (everolimus/sunitinib/somatostatin analogues), chemotherapy, radiological therapy with peptide receptor radionuclide therapy, or liver-directed therapies (embolization/chemoembolization/radio-embolization (SIRTs)) are reviewed. Recent findings in each of these areas, as well as remaining controversies and uncertainties, are discussed in detail, particularly from the viewpoint of treatment sequencing. Conclusions: The recent increase in the number of available therapeutic agents for the nonsurgical treatment of patients with advanced panNENs have raised the importance of prognostic factors predictive for therapeutic outcomes of each treatment option. The establishment of sensitive and useful prognostic markers will have a significant impact on optimal treatment selection, as well as in tailoring the therapeutic sequence, and for maximizing the survival benefit of each individual patient. In the paper, the progress in this area, as well as the controversies/uncertainties, are reviewed.

Therapeutic strategies for gastroenteropancreatic neuroendocrine neoplasms: State-of-the-art and future perspectives

Although gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) have always been considered rare tumors, their incidence has risen over the past few decades. They represent a highly heterogeneous group of neoplasms with several prognostic factors, including disease stage, proliferative index (Ki67), and tumor differentiation. Most of these neoplasms express somatostatin receptors on the cell surface, a feature that has important implications in terms of prognosis, diagnosis, and therapy. Although International Guidelines propose algorithms aimed at guiding therapeutic strategies, GEP-NEN patients are still very different from one another, and the need for personalized treatment continues to increase. Radical surgery is always the best option when feasible; however, up to 80% of cases are metastatic upon diagnosis. Regarding medical treatments, as GEP-NENs are characterized by relatively long overall survival, multiple therapy lines are adopted during the lifetime of these patients, but the optimum sequence to be followed has never been clearly defined. Furthermore, although new molecular markers aimed at predicting the response to therapy, as well as prognostic scores, are currently being studied, their application is still far from being part of daily clinical practice. As they represent a complex disease, with therapeutic protocols that are not completely standardized, GEP-NENs require a multidisciplinary approach. This review will provide an overview of the available therapeutic options for GEP-NENs and attempts to clarify the possible approaches for the management of these patients and to discuss future perspectives in this field.

Long-term treatment with streptozocin/5-fluorouracil chemotherapy in patients with metastatic pancreatic neuroendocrine tumors: Case series

RATIONALE

Pancreatic neuroendocrine tumors (pNETs) are rare entities representing 1% to 3% of all malignant pancreatic neoplasms. Current guidelines recommend a combination of streptozocin (STZ) and 5-fluorouracil (5-FU) for patients with metastatic well-differentiated pNETs requiring systemic therapy. The highest median progression-free survival rate reported in previous studies for this combination was 23 months (95% confidence interval 14.5-31.5). However, it remains unclear for how long this regimen can be safely administered.

PATIENT CONCERNS

We report about 3 therapy-naïve patients with metastatic G2 (Ki67 10%-15%) pNETs treated with STZ/5-FU, that achieved sustained disease control for longer than 36 months.

DIAGNOSIS

Metastatic, well-differentiated G2 pNETs.

INTERVENTIONS

Systemic chemotherapy with STZ/5-FU was administered until the disease progressed. In 1 case showing a mixed response, selected metastases of increasing size were additionally treated with surgery and brachytherapy.

OUTCOMES

In our 3 patients with metastatic G2 pNETs, STZ/5-FU induced long-term disease control over 44, 42, and 95 months, respectively. No side effects that led to treatment discontinuation were observed.

LESSONS

In patients with metastatic G2 pNETs achieving disease control, STZ/5-FU can be safely administered.

Current and New Challenges in the Management of Pancreatic Neuroendocrine Tumors: The Role of miRNA-Based Approaches as New Reliable Biomarkers

Pancreatic neuroendocrine tumors (PanNETs) are rare tumors; however, their incidence greatly increases with age, and they occur more frequently among the elderly. They represent 5% of all pancreatic tumors, and despite the fact that low-grade tumors often have an indolent evolution, they portend a poor prognosis in an advanced stages and undifferentiated tumors. Additionally, functional pancreatic neuroendocrine tumors greatly impact quality of life due to the various clinical syndromes that result from abnormal hormonal secretion. With limited therapeutic and diagnostic options, patient stratification and selection of optimal therapeutic strategies should be the main focus. Modest improvements in the management of pancreatic neuroendocrine tumors have been achieved in the last years. Therefore, it is imperative to find new biomarkers and therapeutic strategies to improve patient survival and quality of life, limiting the disease burden. MicroRNAs (miRNAs) are small endogenous molecules that modulate the expression of thousands of genes and control numerous critical processes involved in tumor development and progression. New data also suggest the implication of miRNAs in treatment resistance and their potential as prognostic or diagnostic biomarkers and therapeutic targets. In this review, we discusses the current and new challenges in the management of PanNETs, including genetic and epigenetic approaches. Furthermore, we summarize the available data on miRNAs as potential prognostic, predictive, or diagnostic biomarkers and discuss their function as future therapeutic targets.

Multimodal Management of Grade 1 and 2 Pancreatic Neuroendocrine Tumors

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

Streptozocin/5-fluorouracil chemotherapy of pancreatic neuroendocrine tumours in the era of targeted therapy

PURPOSE

The role of streptozocin-based chemotherapy (STZ CTx) in advanced, well-differentiated pancreatic neuroendocrine tumours (PanNET) and the best sequence of treatments in advanced PanNET are unclear. We examined the outcomes after STZ CTx in patients who had been selected according to the current therapeutic guidelines.

METHODS

Data from 50 PanNET patients consecutively treated with STZ CTx between 2010 and 2018 were analysed. The endpoints of the study were the objective-response rate (ORR), progression-free survival (PFS), and overall survival (OS).

RESULTS

STZ CTx was the first-line treatment in 54% of patients. The PanNET grades were as follows: 6% G1, 88% G2, and 6% well-differentiated G3. The ORR was 38%. Stable disease was the best response in 38% of patients and 24% showed progressive disease. Treatment was discontinued because of toxicity in one patient. Median PFS and OS were 12 (95% confidence interval (CI), 8.5-15.5) and 38 months (95% CI, 20.4-55.6), respectively. In the Kaplan-Meier analysis, the median OS was 89 months (95% CI, 34.9-143.1) for STZ CTx as first-line therapy compared with 22 months (95% CI, 19.3-24.7; p = 0.001, log-rank test) for subsequent lines. Bone metastases negatively impacted survival (HR, 2.71, p = 0.009, univariate analysis, HR, 2.64, p = 0.015, multivariate analysis, and Cox regression).

CONCLUSIONS

In patients selected according to current guidelines, PFS, and OS after STZ CTx were lower than previously reported, whereas ORR was unchanged. First-line treatment was positively associated with OS and the presence of bone metastases was negatively associated with OS. Pre-treatment with targeted or peptide-receptor radionuclide therapy did not alter ORR, PFS, or OS.

OUP accepted manuscript

Background

The aim of this study was to provide a guidance for the management of neuroendocrine tumors (NETs) in clinical practice.

Material and Methods

Nominal group and Delphi techniques were used. A steering committee of 8 experts reviewed the current management of NETs, identified controversies and gaps, critically analyzed the available evidence, and formulated several guiding statements for clinicians. Subsequently, a panel of 26 experts, was selected to test agreement with the statements through 2 Delphi rounds. Items were scored on a 4-point Likert scale from 1 = totally agree to 4 = totally disagree. The agreement was considered if ≥75% of answers pertained to Categories 1 and 2 (consensus with the agreement) or Categories 3 and 4 (consensus with the disagreement).

Results

Overall, 132 statements were proposed, which incorporated the following areas: (1) overarching principles; (2) progression and treatment response criteria; (3) advanced gastro-enteric NETs; (4) advanced pancreatic NETs; (5) advanced NETs in other locations; (6) re-treatment with radioligand therapy (RLT); (7) neoadjuvant therapy. After 2 Delphi rounds, only 4 statements lacked a clear consensus. RLT was not only recommended in the sequencing of different NETs but also as neoadjuvant treatment, while several indications for retreatment with RLT were also established.

Conclusion

This document sought to pull together the experts’ attitudes when dealing with different clinical scenarios of patients suffering from NETs, with RLT having a specific role where evidence-based data are limited.

Localization Defines Streptozotocin/5-FU Response in Primary Pancreatic Neuroendocrine Tumours

INTRODUCTION

Incidence of pancreatic neuroendocrine tumours (pNETs) is on the rise. The only curative treatment is surgical resection in localized or oligo-metastatic disease. However, patients may present with locally advanced or unresectable primary tumours. So far, no conversion therapy to achieve resectability has been established, which is partly due to lack of data on primary tumour response to therapies. Here, we specifically evaluate the primary tumour response to streptozocin/5-FU in a large cohort of metastatic pNET patients.

METHODS

Five ENETS centres in Germany contributed 84 patients to the study cohort for retrospective analysis.

RESULTS

Overall response rate (ORR) in primary tumours was 34% and disease control rate (DCR) 88%. ORR was different in metastases at 44% and DCR at 70%. Partial remission in primary tumours was more frequent among those located in pancreatic tail than that in pancreatic head (49% vs. 14%, p = 0.03). Correspondingly, metastases from tumours originating from pancreatic tail responded more frequently than metastases originating from pancreatic head (88.5% vs. 41.7%, p = 0.005). The median PFS of the primary tumours was longer than that in metastases (31 months vs. 16 months; p = 0.04). Considerable downsizing of the primary tumour was rare and occurred primarily in tumours located in the pancreatic tail.

CONCLUSION

STZ/5-FU can achieve disease stabilization in a high proportion of metastatic pNET patients. In the majority of cases however it does not induce substantial downsizing of the primary tumour, thus possibly limiting its potential as conversion chemotherapy. Furthermore, the difference in response rate observed between different primary tumour locations warrants further exploration.

Oxaliplatin and 5-Fluorouracil in Advanced Well-Differentiated Digestive Neuroendocrine Tumors: A Multicenter National Retrospective Study from the French Group of Endocrine Tumors

INTRODUCTION

Oxaliplatin-based regimens have shown promising antitumor activity in digestive neuroendocrine tumors (NETs); however, the available data are limited. Our aim was to assess the efficacy of FOLFOX (association of 5-fluorouracil with oxaliplatin) in a large series of patients with advanced digestive NETs.

METHODS

All patients with advanced digestive well-differentiated NETs treated with at least 3 cycles of FOLFOX between January 2004 and December 2018 in 12 centers from the French Group of Endocrine Tumors were included. Tumor response rate according to Response Evaluation Criteria in Solid Tumors version 1.1 criteria, progression free survival (PFS), and overall survival, as well as prognostic factors, were analyzed retrospectively.

RESULTS

One hundred fifty-five patients were included. Primary tumor locations were pancreas (n = 89), small intestine (n = 40), unknown with no evidence for lung primary (n = 13), stomach (n = 7), and rectum (n = 6). Median Ki-67 was 10%, and 65% of the tumors were grade 2. The partial response rate was 30% for pancreatic NETs, 12.5% for small intestine NETs, 38.5% for unknown primary NETs, 14% for gastric NETs, and 17% for rectal NETs. Significant prognostic factors for poor PFS after FOLFOX were progressive disease at the beginning of treatment (hazard ratio [HR] = 1.83, p = 0.007), hepatic involvement superior to 50% (HR = 2.67, p = 0.0001), and rectal primary tumor location (HR = 2.6, p = 0.0036). Among pancreatic NETs, insulinomas had a better median PFS (22 months) than other pancreatic NETs (9 months, p = 0.026) and showed a high rate (8/9) of serum glucose normalization.

CONCLUSIONS

FOLFOX shows a promising antitumor activity in advanced digestive NETs. Rapid symptomatic response is observed in metastatic insulinomas.

Ramucirumab in combination with dacarbazine in patients with progressive well-differentiated metastatic pancreatic neuroendocrine tumors (RamuNET): study protocol for a multicenter single-arm trial

BACKGROUND

Cytotoxic chemotherapy combinations and targeted agents represent established treatment concepts in advanced pancreatic neuroendocrine tumors (PNETs). However, response rates, side effects and outcome data strongly vary among these therapeutic approaches. Head-to-head comparisons between chemo- and molecular therapies are missing and secondary resistances frequently occur. The RamuNET trial aims to identify the effectiveness of dual treatment with DTIC and ramucirumab in progressive advanced PNET patients.

METHODS

The RamuNET study is an investigator-initiated multicenter prospective single-arm trial to evaluate the efficacy of ramucirumab in combination with dacarbazine (DTIC) over a period of at least 6 months. Patients with progressive well-differentiated and metastatic pancreatic neuroendocrine tumors are eligible. The study aims to include 45 patients over a period of 24 months with a minimum follow-up of 24 months. The primary endpoint is disease control after 6 months. Secondary endpoints include progression-free survival, biochemical response, overall survival, quality of life and toxicity. Based on the hypothesis that 80% of the patients can achieve a disease control after 6 months, the sample size calculation follows an exact binomial single-stage design. H0: p < =p0 = 60% versus H1: p > =p1 = 80%, alpha = 0.05, beta = 0.1.

DISCUSSION

This study investigates a new therapeutic approach using the combination of cytotoxic and targeted antiangiogenic therapy in advanced PNET. If positive, this trial will be the basis for a randomized two-arm study to investigate the combination of ramucirumab and DTIC against other established therapies in PNET.

TRIAL REGISTRATION

EudraCT: 2017-001207-68 . Date of registration: 2018.01.03.

Insights into Mechanisms of Tumorigenesis in Neuroendocrine Neoplasms

Genomic studies have identified some of the most relevant genetic players in Neuroendocrine Neoplasm (NEN) tumorigenesis. However, we are still far from being able to draw a model that encompasses their heterogeneity, elucidates the different biological effects consequent to the identified molecular events, or incorporates extensive knowledge of molecular biomarkers and therapeutic targets. Here, we reviewed recent insights in NEN tumorigenesis from selected basic research studies on animal models, highlighting novel players in the intergenic cooperation and peculiar mechanisms including splicing dysregulation, chromatin stability, or cell dedifferentiation. Furthermore, models of tumorigenesis based on composite interactions other than a linear progression of events are proposed, exemplified by the involvement in NEN tumorigenesis of genes regulating complex functions, such as MEN1 or DAXX. Although limited by interspecies differences, animal models have proved helpful for the more in-depth study of every facet of tumorigenesis, showing that the identification of driver mutations is only one of the many necessary steps and that other mechanisms are worth investigating.

Renal function in patients receiving streptozocin for locally advanced or metastatic digestive neuroendocrine tumours: results of the Streptotox-FFCD 0906 study

INTRODUCTION

Streptozocin can impair renal function. The purpose of this study was to evaluate the evolution of renal function in patients receiving this anti-mitotic for the treatment of locally advanced/metastatic digestive well differentiated neuroendocrine tumours.

METHODS

A prospective and a retrospective cohort of patients with normal baseline renal function were analysed. The primary endpoint was the incidence of a decrease in the estimated glomerular filtration rate ≥ 25% during treatment. Secondary endpoints were the evaluation of glomerular filtration rate changes, the impact of combined nephrotoxic treatments, other toxicities, compliance, and the objective response rate.

RESULTS

After screening 142 patients, 27 were included in the prospective and 84 in the retrospective cohort. A decrease in estimated glomerular filtration rate ≥ 25% was observed in 32 patients (30%): respectively four (15.4%) and 28 patients (34.1%) among respectively 26 and 82 patients with numerous measures (P = 0.0097). Altogether, 39 patients (35%) experienced grade 1-2 renal toxicity, while no grade 3-4 occurred in the prospective and 1 occurred in the retrospective cohort. Renal toxicity was more frequent in the retrospective cohort with a less careful follow up. As best responses, objective response was achieved in 27% of patients with pancreatic primary tumours, disease control in 78.9% of patients with pancreatic primary tumours, in 87% of those with small bowel tumours and in 72.7% of patients with other primary locations.

CONCLUSIONS

Strongly recommended for pancreatic NET, streptozocin is associated with frequent mild renal toxicity but low occurrence of renal impairment in patients with baseline normal renal function and under adequate hydration.

Treatment of advanced gastroenteropancreatic neuroendocrine neoplasia, are we on the way to personalised medicine?

Gastroenteropancreatic neuroendocrine neoplasia (GEPNEN) comprises clinically as well as prognostically diverse tumour entities often diagnosed at late stage. Current classification provides a uniform terminology and a Ki67-based grading system, thereby facilitating management. Advances in the study of genomic and epigenetic landscapes have amplified knowledge of tumour biology and enhanced identification of prognostic and potentially predictive treatment subgroups. Translation of this genomic and mechanistic biology into advanced GEPNEN management is limited. 'Targeted' treatments such as somatostatin analogues, peptide receptor radiotherapy, tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors are treatment options but predictive tools are lacking. The inability to identify clonal heterogeneity and define critical oncoregulatory pathways prior to therapy, restrict therapeutic efficacy as does the inability to monitor disease status in real time. Chemotherapy in the poor prognosis NEN G3 group, though associated with acceptable response rates, only leads to short-term tumour control and their molecular biology requires delineation to provide new and more specific treatment options.The future requires an exploration of the NEN tumour genome, its microenvironment and an identification of critical oncologic checkpoints for precise drug targeting. In the advance to personalised medical treatment of patients with GEPNEN, clinical trials need to be based on mechanistic and multidimensional characterisation of each tumour in order to identify the therapeutic agent effective for the individual tumour.This review surveys advances in NEN research and delineates the current status of translation with a view to laying the basis for a genome-based personalised medicine management of advanced GEPNEN.

Finding the Appropriate Therapeutic Strategy in Patients with Neuroendocrine Tumors of the Pancreas: Guideline Recommendations Meet the Clinical Reality

The systemic treatment of patients with pancreatic neuroendocrine tumors is based on placebo-controlled trials and long-established chemotherapy approaches. In addition, peptide receptor radionuclide therapy (PRRT) was approved as a parallel approach for pancreatic neuroendocrine tumors (NET), in addition to small bowel NET, after the NETTER-1 trial. The current ESMO and NCCN guidelines attempted to describe treatment algorithms for pancreatic NET based on the current data. In our survey, we recorded therapy decisions for the first- until the third-line of therapy in German-speaking countries (Germany, Austria, and Switzerland) using fictional case reports and discussed these in the context of the current ESMO guidelines. Compared with the recommendations of the guidelines, PRRT was used more frequently and earlier. In patients with NET G1/G2 Ki-67 < 10%, the therapy algorithm consisting of somatostatin analogs (SSA)-PRRT-targeted therapy is a relevant approach. In clinical situations where chemotherapy is primarily used (remission pressure, Ki-67 > 10%), second-line PRRT was found acceptance and was often considered prior to targeted therapies. Despite the lack of prospective controlled trials, our study demonstrated the pivotal impact of PRRT. Therefore, further studies should compare PRRT with chemotherapy in pancreatic NETs in different clinical settings in first- and second-line approaches.

State of the art and future directions in the systemic treatment of neuroendocrine neoplasms

PURPOSE OF REVIEW

Neuroendocrine neoplasms (NENs) are rare and heterogeneous malignancies whose natural evolution may be defined according to various prognostic factors, including localization of the primitive tumour, hormone secretory status, histological grade, tumour burden, tumour growth rate, expression of somatostatin receptors and fluorodeoxyglucose-avidity. The treatment of these tumours in an advanced setting is based on relatively little robust data.

RECENT FINDINGS

A recent pathological classification introduced a new category of high-grade but well differentiated neuroendocrine tumours (NET G3), with markedly different behaviour from neuroendocrine carcinomas (NECs). Yet, the optimal treatment of those tumours is still uncertain. Advances are needed in molecular subtyping of NENs to understand better their heterogeneity and inform personalized therapies.

SUMMARY

The current review summarizes the current knowledge, indicates some exciting future directions and outlines the most interesting ongoing clinical trials likely to impact current practice.

Nordic guidelines 2021 for diagnosis and treatment of gastroenteropancreatic neuroendocrine neoplasms

BACKGROUND

The diagnostic work-up and treatment of patients with gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) has undergone major advances and new methods are introduced. Furthermore, an update of the WHO classification has resulted in a new nomenclature for GEP-NEN that is implemented in the clinic.

AIM

These Nordic guidelines summarise the Nordic Neuroendocrine Tumour Group's current view on how to diagnose and treat GEP-NEN patients and aims to be useful in the daily practice for clinicians.

Application of carbohydrates in approved small molecule drugs: A review

Carbohydrates are an important energy source and play numerous key roles in all living organisms. Carbohydrates chemistry involved in diagnosis and treatment of diseases has been attracting increasing attention. Carbohydrates could be one of the major focuses of new drug discovery. Currently, however, carbohydrate-containing drugs account for only a small percentage of all drugs in clinical use, which does not match the important roles of carbohydrates in the organism. In other words, carbohydrates are a relatively untapped source of new drugs and therefore may offer exciting novel therapeutic opportunities. Here, we presented an overview of the application of carbohydrates in approved small molecule drugs and emphasized and evaluated the roles of carbohydrates in those drugs. The potential development direction of carbohydrate-containing drugs was presented after summarizing the advantages and challenges of carbohydrates in the development of new drugs.

Systemic Treatment of Advanced Gastroenteropancreatic Neuroendocrine Tumors in Korea: Literature Review and Expert Opinion

Neuroendocrine tumors (NETs) are a group of malignancies arising from neuroendocrine cells and frequently originate in the gastrointestinal tract and pancreas. Although curative resection is the main treatment for localized disease, systemic therapy is needed for relapsed or metastatic/unresectable gastroenteropancreatic NETs (GEP-NETs). Although there are several NET treatment guidelines from various countries, the geographical discrepancies between patient clinical characteristics, the regulatory approval status for therapeutic agents, and medical practices necessitate specific guidelines for Korean patients. We here provide a consensus review of the diagnosis, staging and systemic treatment of Korean GEP-NET patients. Systemic therapy options and the current Korean expert consensus on these treatments, including somatostatin analogs, targeted therapies such as everolimus and sunitinib, peptide receptor radionuclide treatments, and cytotoxic chemotherapies are addressed.

Fluorouracil, Doxorubicin with Streptozocin and Subsequent Therapies in Pancreatic Neuroendocrine Tumors

We evaluated outcomes of treatment with 5-fluorouracil (5-FU), doxorubicin, and streptozocin (FAS) in well-differentiated pancreatic neuroendocrine tumors (PanNETs) and its impact on subsequent therapy (everolimus or temozolomide). Advanced PanNET patients treated at our center from 1992 to 2013 were retrospectively reviewed. Patients received bolus 5-FU (400 mg/m2), streptozocin (400 mg/m2) (both IV, days 1-5), and doxorubicin (40 mg/m2 IV, day 1) every 28 days. Overall response rate (ORR) was assessed using RECIST version 1.1. Of 243 eligible patients, 220 were evaluable for ORR, progression-free survival (PFS), and toxicity. Most (≥90%) had metastatic, nonfunctional PanNETs; 14% had prior therapy. ORR to FAS was 41% (95% confidence interval [CI]: 36-48%). Median follow-up was 61 months. Median PFS was 20 (95% CI: 15-23) months; median overall survival (OS) was 63 (95% CI: 60-71) months. Cox regression analyses suggested improvement with first-line versus subsequent lines of FAS therapy. Main adverse events ≥ grade 3 were neutropenia (10%) and nausea/vomiting (5.5%). Dose reductions were required in 32% of patients. Post-FAS everolimus (n = 108; 68% second line) had a median PFS of 10 (95% CI: 8-14) months. Post-FAS temozolomide (n = 60; 53% ≥ fourth line) had an ORR of 13% and median PFS of 5.2 (95% CI: 4-12) months. In this largest reported cohort of PanNETs treated with chemotherapy, FAS demonstrated activity without significant safety concerns. FAS did not appear to affect subsequent PFS with everolimus; this sequence is being evaluated prospectively. Responses were noted with subsequent temozolomide-based regimens although PFS was possibly limited by line of therapy.

The State of Peptide Receptor Radionuclide Therapy and Its Sequencing among Current Therapeutic Options for Gastroenteropancreatic Neuroendocrine Tumors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are the most common form of neuroendocrine neoplasia, but there is no current consensus for the sequencing of approved therapies, particularly with respect to peptide receptor radionuclide therapy (PRRT). This comprehensive review evaluates the data supporting approved therapies for GEP-NETs and recommendations for therapeutic sequencing with a focus on how PRRT currently fits within sequencing algorithms. The current recommendations for PRRT sequencing restrict its use to metastatic, inoperable, progressive midgut NETs; however, this may change with emerging data to suggest that PRRT might be beneficial as neoadjuvant therapy for inoperable tumors, is more tolerable than other treatment modalities following first-line standard dose somatostatin analogs, and can be used as salvage therapy after disease relapse following prior successful cycles of PRRT. PRRT has also been shown to reduce tumor burden, improve quality of life, and prolong the time to disease progression in a broad spectrum of patients with GEP-NETs. As the various potential benefits of PRRT in GEP-NET therapy continues to expand, it is necessary to review and critically evaluate our treatment algorithms for GEP-NETs.

177Lu-DOTATATE Therapy of Advanced Pancreatic Neuroendocrine Tumors Heavily Pretreated with Chemotherapy: Analysis of Outcome, Safety, and Their Determinants

OBJECTIVE

To retrospectively analyze toxicity, progression-free survival (PFS), overall survival (OS), and their determinants in patients with advanced pancreatic neuroendocrine tumors (PanNETs), previously pretreated with chemothe-r-apy, undergoing peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE.

METHODS

A total of 102 patients with advanced PanNETs, previously pretreated with one (67%) or several (33%) lines of chemotherapy, were included, of whom 90% had progressive disease and the majority (74.5%) had grade 2 tumors. 177Lu-DOTATATE, 7.4 GBq per cycle, was administered with 6- to 8-week intervals in 88% of patients utilizing a dosimetry-guided protocol until an absorbed dose of 23 Gy to the kidneys was reached.

RESULTS

A mean dose of 32 ± 10.9 GBq per patient was administered in 1-10 cycles starting a median of 36 months after PanNET diagnosis. The median follow-up was 34 months, the median PFS was 24 months, and the median OS was 42 months from start of PRRT. Independent risk factors for both progression and death were liver tumor burden >50%, more than one line of previous chemotherapy, and elevated alkaline phosphatase. Resection of the primary tumor was linked to longer survival. Bone marrow toxicity grade 3-4 occurred in 10.8%. One patient (1.0%) developed acute myeloid leukemia. Bone marrow toxicity was unrelated to type and length of previous chemotherapy, amount of administered activity, and absorbed dose to the bone marrow.

CONCLUSION

177Lu-DOTATATE therapy was feasible, highly effective, and safe in patients with advanced PanNETs heavily pretreated with chemotherapy. More than one line of chemotherapy was a therapy-related independent risk factor for shorter PFS and OS.

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.

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.

p53-PHLDA3-Akt Network: The Key Regulators of Neuroendocrine Tumorigenesis

p53 is a well-known tumor suppressor gene and one of the most extensively studied genes in cancer research. p53 functions largely as a transcription factor and can trigger a variety of antiproliferative programs via induction of its target genes. We identified PHLDA3 as a p53 target gene and found that its protein product is a suppressor of pancreatic neuroendocrine tumors (PanNETs) and a repressor of Akt function. PHLDA3 is frequently inactivated by loss of heterozygosity (LOH) and methylation in human PanNETs, and LOH at the PHLDA3 gene locus correlates with PanNET progression and poor prognosis. In addition, in PHLDA3-deficient mice, pancreatic islet cells proliferate abnormally and acquire resistance to apoptosis. In this article, we briefly review the roles of p53 and Akt in human neuroendocrine tumors (NETs) and describe the relationship between the p53-PHLDA3 and Akt pathways. We also discuss the role of PHLDA3 as a tumor suppressor in various NETs and speculate on the possibility that loss of PHLDA3 function may be a useful prognostic marker for NET patients indicating particular drug therapies. These results suggest that targeting the downstream PHLDA3-Akt pathway might provide new therapies to treat NETs.

Achieving objective response in treatment of non-resectable neuroendocrine tumors does not predict longer time to progression compared to achieving stable disease

Background

There are several treatment modalities for unresectable neuroendocrine tumors. Traditionally, the aim of these treatments has been to reduce the tumor load; referred to as objective response (OR). Less emphasis has been put on inducing the tumors to stop growing without a reduction in total tumor load; termed as stable disease (SD). We wanted to investigate whether achieving OR compared to obtaining SD predicted a longer time to progression (TTP) in patients with neuroendocrine tumors (WHO Grade 1 and 2) treated with peptide receptor radionuclide therapy, chemotherapy or molecular targeted therapy.

Methods

Patients treated with either peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lutetium-DOTA-octreotate, the chemotherapy combination streptozotocin/5-fluorouracil or everolimus were retrospectively assessed to evaluate the effect of the treatments on disease progression. We analyzed the TTP for patients for each treatment modality and compared the TTP between those who achieved OR and those who achieved SD.

Results

Altogether 56 patients treated with PRRT, 32 treated with streptozotocin/5-fluorouracil and 52 treated with everolimus were included in the analyses. The median TTP for those treated with PRRT and achieving OR was 31 months, the TTP for those achieving SD was 43 months (p = 0,2). For patients treated with streptozotocin/5-fluorouracil the results were: OR: 18 months, SD: 23 months (p = 0,9) and for those treated with everolimus; OR: 9 months, SD: 20 months (p = 0,5), respectively. We found no differences between patients achieving OR compared to SD regarding age, sex, stage, primary tumor location, Ki-67% or ongoing treatment with somatostatin analogues.

Conclusions

We found no treatment benefit with regard to TTP for our patients that experienced OR compared to those who achieved SD.

Digestive Neuroendocrine Neoplasms (NEN): French Intergroup clinical practice guidelines for diagnosis, treatment and follow-up (SNFGE, GTE, RENATEN, TENPATH, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, SFR)

INTRODUCTION

This document is a summary of the French Intergroup guidelines regarding the management of digestive neuroendocrine neoplasms (NEN) published in February 2020 (www.tncd.org).

METHODS

All French medical societies involved in the management of NEN took part in this work. Recommendations were graded into four categories (A, B, C or D), according to the level of evidence found in the literature until May 2019.

RESULTS

The management of NEN is challenging because of their heterogeneity and the increasing complexity of diagnostic and therapeutic procedures. Pathological analysis is required for their diagnostic and prognostic characterization, which mainly relies on differentiation, grade and stage. The two main emergency situations are functioning syndromes and poorly-differentiated carcinoma. Chromogranin A is the main biochemical marker of NET, although of limited clinical interest. Initial characterization relies on morphological and isotopic imaging. The treatment of localized NET relies on watchful follow-up and local or surgical resection depending on its supposed aggressiveness. Treatment options for metastatic disease include surgery, somatostatin analogues, chemotherapy, targeted therapies, organ-driven locoregional therapies and peptide-receptor radionuclide therapy. As specific predictive factors of treatment efficacy are yet to be identified and head-to-head comparisons have not or only rarely been performed, the therapeutic strategy currently depends on prognostic factors. Cumulative toxicity and the impact of treatment on quality of life must be considered since survival is relatively long in most patients with NET.

CONCLUSION

These guidelines are proposed to achieve the most beneficial therapeutic strategy in clinical practice as the therapeutic landscape of NEN is becoming ever more complex. These recommendations are permanently being reviewed.

Advances in the Diagnosis and Management of Well-Differentiated Neuroendocrine Neoplasms

Neuroendocrine neoplasms constitute a diverse group of tumors that derive from the sensory and secretory neuroendocrine cells and predominantly arise within the pulmonary and gastrointestinal tracts. The majority of these neoplasms have a well-differentiated grade and are termed neuroendocrine tumors (NETs). This subgroup is characterized by limited proliferation and patients affected by these tumors carry a good to moderate prognosis. A substantial subset of patients presenting with a NET suffer from the consequences of endocrine syndromes as a result of the excessive secretion of amines or peptide hormones, which can impair their quality of life and prognosis. Over the past 15 years, critical developments in tumor grading, diagnostic biomarkers, radionuclide imaging, randomized controlled drug trials, evidence-based guidelines, and superior prognostic outcomes have substantially altered the field of NET care. Here, we review the relevant advances to clinical practice that have significantly upgraded our approach to NET patients, both in diagnostic and in therapeutic options.

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.

Therapy of Patients with Neuroendocrine Neoplasia-Evidence-Based Approaches and New Horizons

Neuroendocrine tumors (NETs) show low but increasing incidence and originate in multiple organs, including the pancreas, midgut, caecum, rectum, appendix, colon, and lungs. Due to their stunning genetic, histological, and clinical variability, diagnosis and treatment of NETs are challenging. In addition, low incidence and high variability hamper the implementation of high evidence trials. Therefore, guidelines do not cover the complexity of NETs and, frequently, treatment decisions are taken by interdisciplinary tumor conferences at comprehensive cancer centers. Treatment aims are (i) control of tumor growth, (ii) symptom control, as well as (iii) the improvement of progression-free survival (PFS) and overall survival (OS). Here, we discuss high evidence trials facilitating the achievement of these treatment aims. The majority of the evidence exists for treatment with somatostatin analogue, everolimus, peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lu-DOTATATE, sunitinib, and telotristat. Among those, PRRT is the only treatment option that has the potential to control symptoms, stop tumor growth, and to improve PFS and OS. In contrast, only a low level of evidence exists for treatment with cytotoxic drugs such as streptozotocin and doxorubicine. Finally, we discuss novel treatment options by a combination of cytotoxic drugs, ¹⁷⁷Lu-DOTATATE, and tyrosine kinase inhibitors to be tested in randomized prospective trials in the future. In addition, the application of innovative isotopes, such as ²²⁵Ac, for PRRT is discussed.

Extended cycle streptozotocin/5-FU chemotherapy for maintenance therapy in pancreatic neuroendocrine tumors

PURPOSE

The standard of care treatment for patients with advanced pancreatic neuroendocrine tumors (pNET) is a combination of streptozotocin and 5-FU. Although widely used, little is known about the best long-term strategy with these substances.

METHODS

We here report our experience of 28 patients treated with streptozotocin/5-FU for advanced pNET with special consideration for long-term management using an extended cycle protocol.

RESULTS

Standard 6-weekly Moertel protocol resulted in a median progression-free survival of 21 months (range 3-128) and a median overall survival of 69 months (range 3-157+) in the whole cohort. Thirteen of the 28 patients were switched to an extended 3-month cycle protocol for maintenance therapy. Of these 13 patients, 2 achieved complete remission, 1 partial remission, and 8 stable disease as best response while 2 showed progressive disease following switch to the extended protocol, resulting in an additional median progression-free survival of 23 months. Median overall survival after the start of chemotherapy in this patient group was 69 months (21-157+). Patients benefitted from extended periods free of chemotherapy-associated side effects after switching to the extended cycle protocol.

CONCLUSIONS

Switching to an extended cycle protocol of 3 months for maintenance therapy following initial standard cycles may achieve long-term disease stabilization in selected patients with advanced pNET with good patient acceptance.

Comparison of Temozolomide-Capecitabine to 5-Fluorouracile-Dacarbazine in 247 Patients with Advanced Digestive Neuroendocrine Tumors Using Propensity Score Analyses

INTRODUCTION

Although chemotherapy combining 5-fluorouracil (5FU)-dacarbazine (DTIC) or temozolomide (TEM)-capecitabine (CAP) is extensively used in patients with neuroendocrine tumors (NET), they were never compared. We compared their tolerance and efficacy in advanced NET.

METHODS

We evaluated the records of consecutive patients with pancreatic or small-intestine advanced NET who received 5FU-DTIC or TEM-CAP between July 2004 and December 2017 in 5 French centers. Tolerance, tumor response and progression-free survival (PFS) were compared. Factors associated with PFS were analyzed using Cox multivariate regression model. To reduce the confounding bias of the nonrandomized design, PFS was compared using propensity score analyses.

RESULTS

Ninety-four (5FU-DTIC) patients and 153 (TEM-CAP) patients were included. Pancreatic NET represented 82.3% of cases and 17.1, 61.8 and 10.9% of patients had G1, G2 or G3 NET respectively. Progression at baseline was reported in 92.7% of patients with available data. Grades 3-4 adverse events occurred in 24.7 and 8.5% of TEM-CAP and 5FU-DTIC patients respectively (p = 0.002). The overall response rate was 38.3 and 39.2% respectively (p = 0.596). Median PFS on raw analysis was similar to 5FU-DTIC and TEM-CAP (13.9 vs. 18.3 months, respectively p = 0.86). TEM-CAP was associated with an increased risk of progression on the raw multivariate analysis (hazard ratio [HR] 1.90, 95% CI [1.32-2.73], p = 0.001) and when adjusted on propensity score (HR 1.65, 95% CI [1.18-2.31], p = 0.004).

CONCLUSION

PFS may be longer with 5FU-DTIC than TEM-CAP in patients with advanced NET. Although patients often prefer oral chemotherapy, 5FU-DTIC is a relevant alternative. A randomized comparison is needed to confirm these results.

SEOM clinical guidelines for the diagnosis and treatment of gastroenteropancreatic and bronchial neuroendocrine neoplasms (NENs) (2018)

NENs are a heterogeneous family of tumors of challenging diagnosis and clinical management. Their incidence and prevalence continue to rise across all sites, stages and grades. Although improved diagnostic techniques have led to earlier detection and stage migration, the improved prognosis documented over time for advanced gastrointestinal and pancreatic neuroendocrine tumors also reflect improvements in therapy. The aim of this guideline is to update practical recommendations for the diagnosis and treatment of gastroenteropancreatic and lung NENs. Diagnostic procedures, histological classification and therapeutic options are briefly discussed, including surgery, liver-directed therapy, peptide receptor radionuclide therapy, and systemic hormonal, cytotoxic or targeted therapy, and treatment algorithms are provided.

Systematic review of current prognostication systems for pancreatic neuroendocrine neoplasms

BACKGROUND

Pancreatic neuroendocrine neoplasms are a heterogenous group of rare tumors whose natural history remains poorly defined. Accurate prognostication of pancreatic neuroendocrine neoplasms is essential for guiding clinical decisions. This paper aims to summarize all the commonly utilized and recently proposed prognostication systems for pancreatic neuroendocrine neoplasms published in the literature to date.

METHODS

A systematic review of Pubmed, Scopus, and Embase databases, of the period from January 1, 2000-November 29, 2016, was conducted to identify all published articles reporting on prognostication systems of pancreatic neuroendocrine neoplasms.

RESULTS

A total of 23 articles were included in our review, and a total of 25 classification systems were identified. There were 2 modifications of the World Health Organization 2004 criteria, 4 modifications of the World Health Organization 2010 criteria, 2 modifications of the American Joint Committee on Cancer 2010 staging system, 3 modifications of the European Neuroendocrine Tumor Society 2006 tumor, node, metastasis staging system, 7 novel categorial classification systems, and 2 novel proposed continuous classifications. The most commonly included variables included age, size of tumor, presence of distant and lymph node metastases, Ki-67 index, and mitotic count.

CONCLUSION

Numerous prognostication systems have been proposed for pancreatic neuroendocrine neoplasms, of which the most commonly used systems presently include the World Health Organization 2010 criteria and the two tumor, node, metastasis staging systems by the European Neuroendocrine Tumor Society and the American Joint Commission on Cancer. However, prognostication systems for pancreatic neuroendocrine neoplasms continue to evolve with time as more prognostication factors are identified. More validation and comparative studies are needed to identify the most effective prognostication system.

Effect of Endostar combined with chemotherapy in advanced well-differentiated pancreatic neuroendocrine tumors

The aim of the present study was to assess the effect of Endostar and temozolomide or dacarbazine plus 5-fluorouracil (5-FU) in patients with advanced pancreatic neuroendocrine tumors (pNETs).Phase II study of 14 patients with locally advanced or metastatic well-differentiated pNETs treated between April 2013 and September 2016. Patients received temozolomide or dacarbazine plus 5-FU, and Endostar. The primary outcome was the radiographic response rate.All 14 patients had nonfunctional pNETs. Six patients received temozolomide and 8 received dacarbazine + 5-FU, combined with Endostar. Thirteen patients were assessable for treatment response: 1(7%) with complete response, 5 (39%) with partial response, 5 (39%) with stable disease, and 2 (15%) with progression. The median progression-free survival was 12 months. The most common grade 1/2 toxicities were neutropenia (43%) and leucopenia (21%).Endostar combined with temozolomide or dacarbazine + 5-FU was effective in the treatment of advanced pNETs. The combinations were well tolerated.

Clinical and in vitro studies of the correlation between MGMT and the effect of streptozocin in pancreatic NET

PURPOSE

This study aimed to determine the correlation between DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT) status and the response to streptozocin in advanced well-differentiated pancreatic neuroendocrine tumors (WD panNETs).

METHODS

To test the hypothesis that MGMT deficiency was required for an alkylating drug response, we retrospectively reviewed the response of 13 patients with WD panNETs to alkylating agents in relation to MGMT status. We also studied MGMT expression in streptozocin resistance using panNET cell lines.

RESULTS

The cohort included 54% of patients with and 46% without MGMT expression. Among these, 83.3% (5/6) of MGMT-negative cases showed a partial response to streptozocin. In contrast, only 14.2% (1/7) of MGMT-positive cases showed a partial response (P = 0.013). Induced expression of MGMT in BON1 cells (a panNET cell line with undetectable endogenous MGMT) produced streptozocin resistance. Knockdown of MGMT in QGP1 cells, which express MGMT endogenously, did not alter the response to streptozocin.

CONCLUSIONS

We observed a relationship between MGMT status and streptozocin response in both patients and cell culture. Despite limited cases examined, high concordance of negative expression of MGMT and response to streptozocin treatment suggest that MGMT expression can be a potential biomarker for this treatment.

The Treatment Landscape and New Opportunities of Molecular Targeted Therapies in Gastroenteropancreatic Neuroendocrine Tumors

Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms that originate from neuroendocrine stem cells and express both neural and endocrine markers. They are found in almost every organ, and while NENs are mostly associated with slow growth, complications due to the uncontrolled secretion of active peptides, and metastatic disease, may significantly impair the quality of life and can ultimately lead to the death of affected individuals. Expanding knowledge of the genetic, epigenetic, and proteomic landscapes of NENs has led to a better understanding of their molecular pathology and consequently increased treatment options for patients. Here, we review the principal breakthroughs in NEN treatment management, owing largely to omics technologies over the last few years, current recommendations of systemic treatment, and ongoing research into the identification of predictive and response biomarkers based on molecular targeted therapies.