Role of Endoscopic Ultrasound in Gastroenteropancreatic Neuroendocrine Tumors and Update on Their Treatment

The gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are rare tumors and include all tumors arising from the gastrointestinal (GI) or pancreatic neuroendocrine cells. They can occur anywhere in the GI tract with the small intestine, pancreas and rectum being the common GI sites. Because of nonspecific symptoms they are difficult to diagnose and diagnosis is often delayed by years. Advancement in crosssectional imaging techniques and advent of radionuclide-labeled somatostatin analogs have improved our accuracy of diagnosis and staging GEP NETs. Endoscopic ultrasound (EUS) with its unique combination of endoscopy and ultrasound provides high resolution images of GI tract wall as well as the surrounding solid parenchymal organs and therefore is an important investigation for the diagnosis and staging of GEP NETs. Surgery is the treatment of choice with good long-term results in patients with localized GEP-NETs. Control of symptoms in functional NETs is warranted to improve the quality of life of the patient. Somatostatin and its analogs like octreotide and lanreotide have been used to control symptoms because of functional NETs. The management of metastatic GEP NETs includes control of symptoms and therapy to decrease/stop tumor growth that includes somatostatin and its analogs and chemotherapy. Newer therapeutic modalities like peptide receptor radionuclide therapy (PRRT) and molecular therapy hold considerable promise.