New treatment options with cytotoxic agents in neuroendocrine tumours

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

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

Successful Salvage Chemotherapy with Streptozocin in a Patient with Mediastinal Atypical Carcinoid Tumor Who Had Relapsed after Various Prior Therapies

Pulmonary neuroendocrine tumors are rare, and there have been very few reports regarding optimal chemotherapeutic regimens. Two molecular targeted agents, everolimus and sunitinib, have recently been shown to provide an additional treatment benefit for pulmonary neuroendocrine tumors. However, little information is available regarding the usefulness of streptozocin chemotherapy. Here, we encountered a case of relapsed and refractory mediastinal atypical carcinoid tumor associated with multiple endocrine neoplasia type 1 for various cytotoxic and molecular targeted agents. The patient showed a good response to streptozocin monotherapy. We describe the case and review streptozocin chemotherapy in patients with pulmonary neuroendocrine tumors.

Use of Molecular Profiling to Guide Treatment Decisions in Patients with Neuroendocrine Tumors: Preliminary Results

This case series demonstrates the potential of molecular profiling to improve selection of anti-tumor therapies in the treatment of patients with neuroendocrine and carcinoid tumors. Carcinoid tumors resected at one institution over a 3-year period were sent for molecular profiling to guide choice of treatment. Potentially beneficial therapies were identified based on the measured expression of 20 proteins and oncogenes and a comprehensive review of the chemotherapy response literature. The clinical charts of 41 patients were reviewed retrospectively, and 12 were selected as representatives of the range of effects molecular profiling has on carcinoid treatment. Their presentation, molecular profile results, treatment, and disease progression is reviewed in the following case series. A total of nine patients were treated with drugs identified as potentially beneficial by molecular profile reports. These include capecitabine, 5-fluorouracil, temozolomide, oxaliplatin, and gemcitabine. Based on clinical symptoms, serum markers of disease, and radio-graphic evidence five of nine patients responded to treatment, two had mixed responses, and two did not respond to treatment. At this early juncture, our critique of molecular profiling for neuroendocrine tumors is favorable, as a significant number of our patients responded to drugs identified by molecular profiling as potentially beneficial.

[Drug therapy for neuroendocrine tumours]

The author aims to review the established medical treatment options of neuroendocrine tumours, which have expanded greatly in recent years and present the most important aspects to be considered in planning patients' management. Medical treatment is usually considered in advanced stages of these tumours, as well as in cases of hormone overproduction. Somatostatin analogues have been known to be effective in alleviating hormone excess syndromes, especially carcinoid syndrome for the past 25 years. There is a convincing evidence that the somatostatin analogue octreotide is useful as an antitumor agent, at least in well-differentiated small intestinal neuroendocrine tumours and probably also in those of pancreatic origin. Interferons may be also used and the indications for their use may be almost the same. Optimal patient selection is mandatory for the use of cytotoxic chemotherapy. Streptozotocin- and, recently, temozolomide-based chemotherapies should be considered in progressive phases of well differentiated (G1/G2) pancreatic neuroendocrine tumours. A cisplatin-etoposide combination is the first choice for the treatment of G3 neuroendocrine carcinomas of any origin. Recently, the mammalian target of rapamycin inhibitor everolimus and the combined tyrosine kinase inhibitor sunitinib were registered for the treatment of G1/G2 pancreatic neuroendocrine tumours. The most recent drug treatment recommendations and therapeutic algorithms to improve systemic therapy in patients with neuroendocrine tumours are summarized and novel drug candidates with particular potential for future management of these tumours are outlined.