There are three distinct types of gastric Neuroendocrine tumours using the ENETS classification system. Type 1 gastric NETs are most common, accounting for 5570% of all gastric NETs. Epidemiology studies have suggested an increasing incidence of gastric NETs. Generally type 1 gastric NETs are multifocal in nature and arise in a background of chronic atrophic gastritis. Type 1 Gastric NETs arise from histamine secreting ECL cells, hypergastrinaemia due to excess gastrin release, for example unopposed gastrin secretion occurs in achlorhydria in patients with atrophic gastritis. Management is generally endoscopic surveillance annually to ensure no development of a dominant lesion. The risk of lymph node or distant metastasis is low 15% reported in different series. This risk of metastatic spread is linked to size of lesions. Therefore, the recommendation is for lesions over 10 mm to be removed endoscopically if feasible. This can be performed via endoscopic mucosal resection or endoscopic submucosal dissection. Endoscopic ultrasound prior to resection can be helpful to ensure there is no deep muscle layer involvement. If there is presence of lymph node involvement or the primary tumour appears advanced on imaging (T2 disease or greater) surgery can be considered. This would involve local resection if possible. The role of antrectomy is unclear in terms of causing regression of these lesions. However, can be considered in individual cases if recurrent large tumours are occurring. Medical therapy in terms of somatostatin analogues is generally reserved for patients with metastatic disease who have positive uptake on somatostatin based function imaging. There may also be a role for gastrin receptor antagonist netazepide, which has demonstrated anti-proliferative properties in gastric NETs. However, further studies are required.
04 Dec 2017
UK and Ireland Neuroendocrine Tumour Society