Molecular targeted therapies in the treatment of gastroenteropancreatic neuroendocrine tumors

Systemic Therapies for Advanced Gastrointestinal Carcinoid Tumors

Well-differentiated gastrointestinal neuroendocrine tumors (GINETs) tend to be slow growing, but treatment of advanced disease remains a challenge. Somatostatin analogues (SSAs) are considered standard therapy for carcinoid syndrome. SSAs delay tumor progression in advanced well-differentiated gastroenteropancreatic NETs. Cytotoxic chemotherapy and interferon play a limited role in the treatment of nonpancreatic GINETs. There is no standard approach to treatment of patients with disease progression. Identification of systemic agents with antitumor activity in advanced disease remains an unmet medical need. Enrollment to clinical trials is encouraged; potential therapeutic targets include the vascular endothelial growth factor and mammalian target of rapamycin signaling pathways.

Duodenal gangliocytic paraganglioma, a rare entity among GEP-NET: a case report with immunohistochemical and molecular study

Gastroenteropancreatic neuroendocrine tumors are the most incident neuroendocrine tumors. In the new WHO classification (2010) the embryological derivation of each neoplastic entity is one of the most important parameters. Gangliocytic Paraganglioma is a tumor originating in the hindgut, a rare neoplasm, generally affecting the second portion of the duodenum, the majority of which are benign.

Cases of gangliocytic paraganglioma with local metastasis or local recurrence have also been reported.

We describe a GP in a 48-year-old caucasian male with an unusual site (4th portion of duodenum) and an interesting immunohistochemical and molecular pattern. In particular, we examined the expression of some neuroendocrine markers and a marker of neuronal differentiation, NeuroD1, whose expression can help to better understand the nature of this neoplasia.

Malignant neuroendocrine tumour of the gallbladder with elevated carcinoembryonic antigen: case report and literature review

A 58-year-old woman presented to a tertiary care centre with signs and symptoms of acute cholecystitis, cholelithiasis and diagnoses of a high-grade neuroendocrine tumour of the gallbladder primarily with peritoneal and liver metastases. She had a liver abscess secondary to Salmonella and Enterococcus fecalis that was drained and treated with appropriate antibiotics. Interestingly, the serum chromogranin A levels were within normal limits, but carcinoembryonic antigen was elevated, which helped evaluate responses and pick progression. She was treated with 10 cycles of palliative chemotherapy when malignancy associated complications started to recur, that is, cholangitis, worsening pain, cachexia, intestinal obstruction, etc leading to chemotherapy delays. Her disease progressed during these times with rapid deterioration of performance status. She died of septic complications postlaparotomy for intestinal obstruction. Her progression-free survival remained for 8 months with subjective and objective improvements, and her overall survival remained at 13 months. We describe the course of her illness and give a brief review of the literature.

Therapy of metastatic pancreatic neuroendocrine tumors (pNETs): recent insights and advances

Neuroendocrine tumors (NETs) [carcinoids, pancreatic neuroendocrine tumors (pNETs)] are becoming an increasing clinical problem because not only are they increasing in frequency, but they can frequently present with advanced disease that requires diagnostic and treatment approaches different from those used in the neoplasms that most physicians are used to seeing and treating. In the past few years there have been numerous advances in all aspects of NETs including: an understanding of their unique pathogenesis; specific classification systems developed which have prognostic value; novel methods of tumor localization developed; and novel treatment approaches described. In patients with advanced metastatic disease these include the use of newer chemotherapeutic approaches, an increased understanding of the role of surgery and cytoreductive methods, the development of methods for targeted delivery of cytotoxic agents, and the development of targeted medical therapies (everolimus, sunitinib) based on an increased understanding of the disease biology. Although pNETs and gastrointestinal NETs share many features, recent studies show they differ in pathogenesis and in many aspects of diagnosis and treatment, including their responsiveness to different therapies. Because of limited space, this review will be limited to the advances made in the management and treatment of patients with advanced metastatic pNETs over the past 5 years.

Innovations therapy: mammalian target of rapamycin (mTOR) inhibitors for the treatment of neuroendocrine tumors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare neoplasms that require a multidisciplinary approach for an optimal management. The lack of effectiveness of traditional DNA-damaging agents has led to the exploration of new targeted drugs in order to exploit phenotypical features of GEP-NET therapy. However, due to the orphan setting of these tumors, deeper characterization of molecular features and pathways that characterize cell growth, apoptosis, angiogenesis, and invasion are lacking, particularly genetic mutations or epigenetic alterations that generate oncogenic dependency or even addiction. The PI3K-AKT-mTOR pathway has been implicated as having a crucial role in GEP-NETs not only due to the overexpression of several growth factors and their receptors that finally activate this axis but also hereditary syndromes with constitutive activation of the mTOR pathway with high incidence of GEP-NETs. In this article, we aim to review the recent development of the main molecules that target mTOR complex and have showed promising activity in the treatment of GEPNETs.

Novel anticancer agents in clinical trials for well-differentiated neuroendocrine tumors

Neuroendocrine tumors (NETs) are rare malignancies that arise from endocrine cells located in various anatomic locations, with a dramatic increase in incidence during the last 30 years. Limited therapeutic options are currently available for patients with advanced well-differentiated NETs, including carcinoids and pancreatic NETs. Streptozotocin-based chemotherapy and somatostatin analogues are drugs that are currently used for the treatment of progressive metastatic NETs. Recently, sunitinib demonstrating efficacy in pancreatic islet cell carcinomas has opened a new avenue for the treatment of NETs, and further trials shall be considered in NET types such as carcinoids, poorly differentiated neuroendocrine carcinomas, and several other endocrine tumors that depend on vascular endothelial growth factor (VEGF)/VEGF receptor for angiogenesis. In addition, drugs with distinct mechanisms of action, such as mammalian target of rapamycin inhibitors, currently investigated in phase 3 trials, may also supply novel options to control tumor growth and metastasis. Although acknowledged as rare tumors, recent data demonstrated the feasibility of large randomized trials in this disease. Furthermore, data from large trials also showed the importance of selecting an appropriate patient population when designing randomized studies. This review focuses on novel therapeutic approaches in the treatment of well-differentiated NETs. Based on recent data, novel strategies may now be designed using those anticancer agents to optimize the current treatment of patients with NETs.