Neuroendocrine tumors are rare, small, slow-growing epithelial neoplasms with predominant neuroendocrine differentiation found in most organs of the body.
They arise from cells throughout the diffuse endocrine system.
Carcinoid tumors and pancreatic neuroendocrine tumors are the most common.
Carcinoid tumors arise from the lungs & bronchi, stomach, small intestine, appendix, rectum or thymus.
Majority of the neuroendocrine tumors are sporadic but some tumors are caused by inherited genetic syndromes such as multiple endocrine neoplasia, Von-Hippel Lindau disease, tuberous sclerosis complex and neurofibromatosis.
They have the ability to store and secrete various peptides and neuroamines.

Follow Up

  • NETs are slow growing but they may progress faster if they are poorly differentiated or have a high Ki67 index > 5%
  • Patients should be monitored more closely during the first year after diagnosis to determine the status of the disease
    • Assess clinical manifestations, biomarkers, presence of new sites of disease, & quality of life during treatment
    • Routine evaluations, such as echocardiogram for patients w/ elevated 5-HIAA, to detect carcinoid heart disease in its early stages can improve prognosis
  • PET scan & somatostatin scintigraphy are not advised for routine surveillance
  • It is recommended to have re-evaluation of the patient 3-12 months after surgical resection or earlier if the patient is symptomatic
    • >1 year following surgical resection, every 6-12 months is recommended schedule for follow-up
    • Abdominal or pelvic multiphasic CT or MRI, gastrin, CgA & 5-HIAA levels may be used for disease monitoring
  • Low-risk patients (eg carcinoid tumor of the appendix) usually require no follow-ups
    • Low-risk patients are those having <2 cm primary tumor (<1 cm for rectal tumors), no nodal involvement & have low Ki67 < 5%
  • Repeat rectal MRI or endoscopic ultrasound 6-12 months after initial treatment is recommended for rectal NETs 1-2 cm in size & for gastric NETs type 1 or 2 for the 1st 3 months then annually if negative for pathologies
Digital Edition
Asia's trusted medical magazine for healthcare professionals. Get your MIMS Gastroenterology - Malaysia digital copy today!
Editor's Recommendations
Most Read Articles
31 Jan 2018
Treatment with proton pump inhibitors (PPIs) appears to increase the risk of death during hospitalization in the presence of pyogenic liver abscess, according to a study.
28 Jun 2017
Intra- and/or postoperative blood transfusion (BT) may increase the risk of postoperative infections complications in patients with Crohn’s disease (CD), according to a study.
18 Oct 2016
EndoClot has been shown to help in the management of gastrointestinal (GI) bleeding whether as a monotherapy or in combination with other techniques from oozing bleeding type or lower, according to a recent study.
Stephen Padilla, 22 Dec 2017
A correlation exists between coeliac disease and a heightened risk of pneumococcal infection, according to a recent study, adding that vaccination must be considered for those with the disease, especially those aged 15‒64 years who have not received the scheduled pneumococcal vaccination series when they were young.