Abstract
Diarrhea is a recurrent symptom in patients with neuroendocrine tumors (NETs) and can represent different etiologies; thus, differential diagnosis is challenging. This paper distinguishes the different causes of chronic diarrhea in patients with gastroenteropancreatic NETs, with the aim to identify the most appropriate therapeutic approach. Underlying causes of diarrhea can be multifactorial, including not only diarrhea that is related to specific hormonal hypersecretory syndromes, but also diarrhea that is secondary to the following: extensive surgery which can cause pancreatic exocrine insufficiency or short bowel syndrome, treatment with somatostatin analogs or other antineoplastic agents, and bile acid malabsorption. After initial management of diarrhea with general treatments (dietary modification, use of antidiarrheals), a proper differential diagnosis is necessary to treat patients with specific etiology-driven therapeutic approaches, such as somatostatin analogs, pancreatic enzyme replacement therapy, and tryptophan hydroxylase inhibitors. In conclusion, NETs should be considered in the differential diagnosis of patients suffering from chronic diarrhea, after the exclusion of more common etiologies. Furthermore, physicians should keep in mind that several different etiologies might be responsible for diarrhea occurrence in NET patients. A prompt diagnosis of the actual cause of diarrhea is necessary to guide the treatment and a multidisciplinary approach is mandatory.
Highlights
Neuroendocrine tumors (NETs) represent a heterogeneous group of tumors arising from enterochromaffin cells with characteristics of both nervous system and hormone-producing cells
neuroendocrine tumors (NETs) should be considered in the differential diagnosis of patients suffering from chronic diarrhea, after the exclusion of more common etiologies
For patients with metastatic NETs, diarrhea remains a major clinical problem with high symptom burden resulting in reduced quality of life (QoL) and negative financial impact
Summary
Neuroendocrine tumors (NETs) represent a heterogeneous group of tumors arising from enterochromaffin cells with characteristics of both nervous system and hormone-producing cells. The crude incidence of gastrointestinal NETs or gastroenteropancreatic (GEP) has markedly increased over the last years and is estimated to be 5.25/100,000/year with a prevalence of 35/100,000/year [4]. The most prevalent symptoms in patients with GEP NETs include diarrhea, fatigue, abdominal discomfort, flushing, and food intolerance [5]. It is important to keep in mind that other etiologies might be responsible for the occurrence of chronic diarrhea in NET patients. This narrative review, based on the available literature and the authors’ experience, intends to help the physician distinguish among the different causes of diarrhea in patients with GEP NETs and to assist in identifying the most appropriate therapeutic approach
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