Gastrointestinal neuroendocrine tumors in 2020

Table 4 Appendiceal neuroendocrine tumor: Size and surgery

Appendiceal NET size	Surgery
< 1 cm	Simple appendectomy
1 cm to 2 cm	Appendectomy and periodic post-operative follow up is recommended for 5 yr. Right hemicolectomy should be considered in the presence of involvement of base of the appendix, cecal infiltration, invasion into the mesoappendix or serosa, involvement of tumor margin, positive lymph nodes, lymphovascular invasion, presence of goblet cells or poorly differentiated cells, Ki67 index > 2% or MiNEN
> 2 cm	Right hemicolectomy within 3 mo from the time of appendectomy but staging work up is required. This includes multiphasic computerized tomography or magnetic resonance imaging of abdomen and pelvis. SRS-based scan (Octreoscan) or (68)Ga-DOTATE PET/CT, serum CgA, 24 h 5-HIAA and colonoscopy to evaluate for synchronous colorectal cancer

NET: Neuroendocrine tumors; (68)Ga-DOTATE PET/CT scan: Gallium -68 DOTATE positron emission tomography/computerized tomography scan; CgA: Chromogranin A; 5-HIAA: 5 hydroxylindoleacetic acid; MiNEN: Mixed neuroendocrine neoplasm.