Efficacy of treatments for VIPoma: A GTE multicentric series

Management of functional neuroendocrine tumors

Functional neuroendocrine neoplasms (NENs) are those associated with specific symptoms related to the hormonal secretion of the NENs. Although less than 25 % of NENs are functional at diagnosis,1 the associated syndromes significantly increase the patient burden of disease. Management of hormonal NEN symptoms may involve tumor resection or other reduction strategies (e.g., chemotherapy, embolotherapy, etc), but also specific therapies directed at decreasing hormonal synthesis, secretion, or end-organ effects. In this review, we focus on specific symptomatic management of many of the NEN syndromes, which may be pursued in addition to management primarily directed at tumor bulk and growth. A continued focus on symptom management related to the hormonal secretions of NENs, in the context of other efforts to reduce tumor bulk and growth, could significantly improve patient wellbeing.

Characteristics, therapy, and outcome of rare functioning pancreatic neuroendocrine neoplasms

Functioning pancreatic neuroendocrine neoplasms other than insulinomas and gastrinomas (rf-pNENs) are exceptionally rare tumours. Thus, their characteristics and long-term prognosis have not been well defined. This article aims to present data and experience from a single institution concerning this topic. Twelve of 216 (5.5%) patients with pNENs operated between 2002 and 2022 in the ENETS Centre of Excellence Marburg had rf-pNENs and their data were retrospectively analysed. We identified three vasoactive intestinal polypeptide producing pNENs, four glucagonomas and five calcitoninomas. The tumour could be visualised by preoperative imaging in all 12 patients, and six patients had distant metastases at the time of diagnosis. The tumour was located in the pancreatic tail in nine patients and the median tumour size was 82 (range 12-220) mm. Eleven patients underwent tumour resections (two robotic, nine conventional), nine of which were R0. After a median follow-up of 75 (range 1-247) months, six patients were alive, five of whom had no evidence of disease. All patients who remained disease-free had an initial R0 resection of the primary tumour and no initial liver involvement. This study sheds light on the distinct characteristics and outcomes of these exceedingly rare tumours, offering insights for improved understanding and management.

Interference With VIP to Distinguish Between Real and False VIPoma: National Study From the French Endocrine Tumors Group

Background

Vasoactive intestinal peptide (VIP)-secreting tumors (VIPomas) are digestive neuroendocrine tumors in which the hormonal secretion is life-threatening. Biological confirmation is obtained by demonstrating an elevation in plasma VIP, usually using radioimmunoassay (RIA). In some cases, analytical interference is suspected. We developed 3 different techniques to detect interference in VIP RIA.

Methods

Three techniques were used: RIA after Sephadex column chromatography separation, RIA after polyethylene glycol precipitation, and 125I-labeled VIP binding test. We included patients with suspicion of false positive VIP (FPV) elevation. We then compared results with those of a group of "real," proven VIPoma (RV).

Results

A total of 15 patients with FPV elevation and 9 RV patients were included. Interference was detected in all FPV patients vs none in RV. Clinical and biochemical parameters did not differ between FPV and RV patients, but VIP concentration in RIA was significantly higher in FPV patients than in RV patients (228 pmol/L vs 66 pmol/L, P = .038). Using a 125I-labeled VIP binding test, median proportion of radioactivity in the pellet was significantly higher in FPV than in RV patients (53% vs 13%, P < .0001). A 20.5% threshold presented excellent performances (sensitivity 100% [79.6-100], specificity 100% [70.1-100]).

Conclusion

We developed 3 different laboratory techniques to reveal interference in RIA VIP assays. The diagnostic performance of all 3 was excellent. These techniques must be employed in cases of discordance between VIP elevation and clinical presentation.

Chronic Diarrhea Caused by Vasoactive Intestinal Peptide-Secreting Tumor

VIPomas are a type of neuroendocrine tumor that independently produces vasoactive intestinal peptide (VIP). VIPomas causing watery diarrhea, hypokalemia, and achlorhydria (WDHA) syndrome are not frequently observed in adult patients without pancreatic ailments. However, in children, the occurrence of a VIPoma originating in the pancreas is exceedingly uncommon. Instead, WDHA syndrome is more commonly associated with neurogenic tumors that secrete VIP, often located in the retroperitoneum or mediastinum. Among infants, chronic diarrhea is a prevalent issue that often necessitates the attention of pediatric gastroenterologists. The underlying causes are diverse, and delays in arriving at a definitive diagnosis can give rise to complications affecting the overall well-being of the child. The authors present the case of an infant with chronic watery diarrhea, subocclusion manifestations, mild hypokalemia, and metabolic hyperchloremic acidosis secondary to a VIPoma in the retroperitoneum that was diagnosed via abdominal ultrasound and tomography. The laboratory results revealed lowered potassium levels and an excessive secretion of VIP. Following the surgical removal of the tumor, the diarrhea resolved, and both electrolyte levels and the imbalanced hormone levels returned to normal. Immunohistochemical examination confirmed the diagnosis of ganglioneuroblastoma, with N-MYC negative on molecular biology tests. We present the clinical and histo-genetic aspects of this rare clinical entity, with a literature review.

Effective strategies for adequate control of hormonal secretion in functioning neuroendocrine neoplasms

Neuroendocrine neoplasms are a unique form of malignancies as they can be accompanied by specific functioning hormonal syndromes that can impair survival and quality of life in patients. Functioning syndromes are defined by the combination of specific clinical signs and symptoms in combination with inappropriately elevated circulating levels of hormones. Clinicians should remain vigilant for the presence of functioning syndromes in neuroendocrine neoplasm patients at presentation as well as during follow-up. The correct diagnostic work-up should be initiated in cases of clinical suspicion of a neuroendocrine neoplasm-associated functioning syndrome. Management of a functional syndrome includes options from supportive, surgical, hormonal and antiproliferative treatment modalities. Here, we review the patient and tumour characteristics for each functioning syndrome that should be taken into account when deciding the optimum treatment strategy in neuroendocrine neoplasm patients.

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

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

European Neuroendocrine Tumor Society 2023 guidance paper for functioning pancreatic neuroendocrine tumour syndromes

This ENETS guidance paper aims to provide practical advice to clinicians for the diagnosis, treatment and follow-up of functioning syndromes in pancreatic neuroendocrine tumours (NET). A NET-associated functioning syndrome is defined by the presence of a clinical syndrome combined with biochemical evidence of inappropriately elevated hormonal levels. Different hormonal syndromes can be encountered in pancreatic NET patients, including insulinoma, gastrinoma as well as the rare glucagonoma, VIPoma, ACTHoma, PTHrPoma, carcinoid syndrome, calcitoninoma, GHRHoma and somatostatinoma. The recommendations provided in this paper focus on the biochemical, genetic and imaging work-up as well as therapeutic management of the individual hormonal syndromes in well-differentiated, grade 1-3, functioning NET with the primary tumour originating in the pancreas, and for specific subtypes also in the duodenum.

An Insight on Functioning Pancreatic Neuroendocrine Neoplasms

Pancreatic neuroendocrine neoplasms (PanNENs) are rare neoplasms arising from islets of the Langerhans in the pancreas. They can be divided into two groups, based on peptide hormone secretion, functioning and nonfunctioning PanNENs. The first group is characterized by different secreted peptides causing specific syndromes and is further classified into subgroups: insulinoma, gastrinoma, glucagonoma, somatostatinoma, VIPoma and tumors producing serotonin and adrenocorticotrophic hormone. Conversely, the second group does not release peptides and is usually associated with a worse prognosis. Today, although the efforts to improve the therapeutic approaches, surgery remains the only curative treatment for patients with PanNENs. The development of high-throughput techniques has increased the molecular knowledge of PanNENs, thereby allowing us to understand better the molecular biology and potential therapeutic vulnerabilities of PanNENs. Although enormous advancements in therapeutic and molecular aspects of PanNENs have been achieved, there is poor knowledge about each subgroup of functioning PanNENs.Therefore, we believe that combining high-throughput platforms with new diagnostic tools will allow for the efficient characterization of the main differences among the subgroups of functioning PanNENs. In this narrative review, we summarize the current landscape regarding diagnosis, molecular profiling and treatment, and we discuss the future perspectives of functioning PanNENs.

A clinical analysis on functioning pancreatic neuroendocrine tumors (focusing on VIPomas): a single-center experience

VIPomas are generally rare functioning pancreatic neuroendocrine tumors (PanNETs) that cause watery diarrhea, hypokalemia, and achlorhydria. Due to their extreme rarity, the clinicopathological features and outcomes of VIPomas have not been well reported. This study aimed to determine the diagnostic and therapeutic characteristics and prognosis of VIPomas and to compare them with other PanNETs at a Japanese reference hospital. Medical records of 293 patients with PanNETs were collected. Patient and tumor characteristics and outcomes were retrospectively reviewed. This cohort had only 1.4% (four patients) of patients with VIPomas, and three of these patients changed from non-functioning (NF-) PanNETs during their disease course. Recurrences of hormonal symptoms were observed in all patients despite the initial controls, and all of them died from their disease, more specifically mainly from hormonal symptoms. Compared to the other PanNETs, VIPomas were all located at the pancreatic tail, were larger, and had a higher Ki-67 index and more metastasis. The median survival time was significantly shorter for patients with VIPoma than for those with NF-PanNET (5.9 vs. 26.7 years, p < 0.0001), insulinoma (21.8 years, p < 0.0001), and gastrinoma (12.3 years, p = 0.0325). This study presents the possibility of shifting from non-symptomatic to symptomatic VIPomas as they grow or of transforming from NF-PanNETs to VIPomas. VIPomas should be considered in patients with relatively large NF-PanNETs, especially those located in the pancreatic tail, when diarrhea is continuously observed. As hormonal symptoms are an important cause of death in VIPomas, long-term symptomatic control, which is relatively difficult, is of great significance.

Treatment options of metastatic and nonmetastatic VIPoma: a review

PURPOSE

VIPoma belongs to the group of neuroendocrine neoplasms. These tumours are located mostly in the pancreas and produce high levels of vasoactive intestinal peptide (VIP). In most cases, a metastatic state has already been reached at the initial diagnosis, with high levels of VIP leading to a wide spectrum of presenting symptoms. These symptoms include intense diarrhoea and subsequent hypopotassaemia but also cardiac complications, with life-threatening consequences. Treatment options include symptomatic therapy, systemic chemotherapy and targeted therapy, as well as radiation and surgery. Due to the low incidence of VIPoma, there are no prospective studies or evidence-based therapeutic standards to date.

METHODS

To evaluate the possible impact of different therapy strategies, we performed literature research using PubMed.

RESULTS

All possible treatment modalities for VIPoma have at least one of two therapy goals: antisecretory effects (symptom control) and antitumoural effects (tumour burden reduction). Symptomatic therapy is the most important in the emergency setting to rehydrate, balance electrolytes and stabilise the patient. Symptomatic therapy is also of great importance perioperatively. Somatostatin analogues play a major role in symptom control, although their efficiency is often limited. Chemotherapy may be effective in reaching stable disease for a certain time period, although its impact on symptom control is limited and often delayed. Among targeted therapy options, the usage of sunitinib appears to be the most effective in terms of symptom control and showing antitumoural effects at the same time. Experience with radiation is still limited; however, local ablative procedures seem to be promising options. Peptide receptor radiotherapy (PRRT) with radiolabelled somatostatin analogues (SSAs, 177Lu-DOTATATE) offers a targeted approach, especially in patients with high somatostatin receptor density. Surgery is the first-line therapy for nonmetastatic VIPoma. Additionally, if the resection of all visible tumour lesions is possible, the surgical approach seems preferable to other strategies in highly symptomatic patients. The role of surgery in very advanced stages where only tumour debulking is possible remains debatable. However, a high rate of immediate symptom control can be achieved by tumour debulking followed by somatostatin therapy, although the impact on survival remains unclear.

CONCLUSION

Surgery is the only curative option for nonmetastatic VIPoma. Additionally, surgery should be a first-line therapy option for highly symptomatic patients, especially if the resection of all tumour lesions (primary tumour and metastasis) is achievable. In frail patients, other modalities can be used.