Initial Evaluation
For evaluation of duodenal, jejunal, ileal, and colonic neuroendocrine tumors (NETs), the National Comprehensive Cancer Network (NCCN) recommends abdominal/pelvic multiphasic CT or MRI and any of the following as appropriate
:
Somatostatin receptor scintigraphy
Colonoscopy
Small-bowel imaging (CT enterography or capsule endoscopy)
Chest CT
Biochemical evaluation if clinically indicated by symptoms of hormone secretion
For evaluation of T1 rectal NETs, the NCCN recommends endorectal MRI or endoscopic ultrasound (EUS); for T2-T4 rectal NETs, recommended studies are as follows:
Colonoscopy
Abdominal/pelvic multi-phasic CT or MRI
Endorectal MRI or EUS
In addition, the following are recommended to be done, as appropriate:
Somatostatin receptor scintigraphy
Chest CT
Biochemical evaluation if clinically indicated
For evaluation of gastric NETs, NCCN recommendations are as follows:
Esophagogastroduodenoscopy (EGD)
Gastric biopsy
Serum gastrin level
Consider gastric pH, as appropriate
For evaluation of bronchopulmonary NETs, the NCCN recommends chest CT and abdominal multiphasic CT or MRI, with the following as appropriate:
Somatostatin receptor scintigraphy
Bronchoscopy
Biochemical workup for Cushing syndrome, if clinically indicated
Other biochemical evaluation, as clinically indicated
For evaluation of thymus NETs, the NCCN recommends chest/mediastinal multiphasic CT and abdominal multiphasic CT or MRI, the following as appropriate:
Somatostatin receptor scintigraphy
Bronchoscopy
Biochemical workup for Cushing syndrome, if clinically indicated
Other biochemical evaluation, as clinically indicated
European Neuroendocrine Tumor Society (ENETS) consensus guidelines for high-grade gastroenteropancreatic neuroendocrine tumors, issued in 2016, include the following minimal consensus recommendations on diagnosis
:
Clinical signs and symptoms should guide the appropriate diagnostic procedures
Chromogranin A and neuron-specific enolase (NSE) testing is not mandatory, but may be useful if levels are elevated at diagnosis; other hormone tests are not routinely recommended
A minimal diagnostic workup should include site-specific endoscopic assessment with tumor biopsy, and whole-body CT scan (and/or MRI) for tumor staging
In patients with metastatic disease, an ultrasound-guided percutaneous biopsy may be performed if feasible
Somatostatin receptor scintigraphy is not routinely indicated but may be considered in tumors with proliferative indexes in the low range of G3 (Ki-67 < 55%)
Bone scans or brain imaging (CT or MRI) should not be performed in the absence of site-specific symptoms
Fluorodeoxyglucose positron emission tomography (FDG-PET) may be considered in patients in whom radical surgery is being pursued or if clarification of equivocal findings on conventional imaging may change the therapeutic approach; FDG-PET may be useful in resectable cases for whole-body assessment