Neuroendocrine tumors of the stomach (gastric carcinoids) are on the rise: small tumors, small problems?

Abstract

Well differentiated neuroendocrine tumors (NETs) of the stomach (gastric carcinoid tumors) are observed more often, with a tenfold increase in the US in the last 30 - 35 years, and the prognosis has improved greatly in that time. Nowadays most carcinoids of the stomach are diagnosed at an early stage. Four types of gastric NETs have been proposed and recognition of the type is important for defining the diagnostic approach and treatment. Often gastric NETs (especially type 1) are found incidentally during a gastroscopy performed for other reasons; most of these NETs are smaller than 20 mm in size. Conservative management and endoscopic surveillance is adequate for well differentiated, multifocal gastric carcinoids (type 1 or type 2 gastric NETs) that are less than 10 - 20 mm in diameter, unless they show angioinvasion, infiltrate the muscular wall, or have a proliferation rate above 2 %. Endoscopic ultrasound is the method of choice to determine tumor size and depth of infiltration. It is essential to distinguish between multifocal (types 1 and 2) and unifocal type 3 or type 4 gastric NETs, since surgery is indicated for type 3 gastric NETs larger than 10 mm in diameter and for poorly differentiated (localized) neuroendocrine gastric carcinomas (type 4 gastric NET). For optimal management, the type, biology, and stage of the tumor as well as the individual situation of the patient must be considered. Most patients with well differentiated gastric NETs can be treated conservatively and be followed up with endoscopic surveillance.