Diagnosis of neuroendocrine tumors (NET) may be based on1:
- Clinical symptoms
- Tests measuring hormones, biochemical tumor markers, and other markers
- Imaging tests, such as computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and somatostatin receptor scintigraphy (SRS)
Read more about functioning and nonfunctioning NET here.
Tests measuring hormones
Two key markers of NET are 5-hydroxyindoleacetic acid (5-HIAA) and chromogranin A (CgA)2:
- An elevated 5-HIAA level is associated with a classic carcinoid syndrome of flushing and diarrhea
- Measurement of CgA is considered the gold standard of biochemical tests for confirming a diagnosis of NET, with high levels of CgA indicating a high tumor burden
Diagnostic imaging plays a key role in diagnosing and monitoring NET. There are multiple imaging techniques available to diagnose, localize, stage, and monitor the progression of NET:
- OctreoscanTM—a sensitive imaging technique2
OctreoscanTM (somatostatin receptor scintigraphy) of a patient with liver metastasis from a carcinoid tumor. The primary tumor located in the distal ileum also is present in the figure.
- Spect/CT hybrid imaging in SRS with triple phase CT scanning3
- MIBG (iodine-131-metaiodobenzylguanidine) scanning2
CT picture of liver metastases in a patient with an endocrine pancreatic tumor.
- Endoscopic ultrasound2
Ultrasonography of liver metastases from a patient with carcinoid tumor. Ultrasound-guided biopsy can be taken during this procedure.
- Capsule endoscopy or camera pill2
Octreoscan is a trademark of Curium.
Routinely monitor for progression4
• Perform CT or MRI scan every 3 to 6 months for NET
• CgA is the most practical and useful general serum tumor marker in patients with NET
1. Vinik AI, Woltering EA, O’Dorisio TM, Go VLW, Mamikunian G. Neuroendocrine Tumors: A Comprehensive Guide to Diagnosis and Management. 5th ed. Inglewood, CA: Inter Science Institute; 2012. 2. Modlin IM, Kidd M, Latich I, Zikusoka MN, Shapiro MD. Current status of gastrointestinal carcinoids. Gastroenterology. 2005;128:1717-1751. 3. Hillel PG, van Beek EJR, Taylor C, et al. The clinical impact of a combined gamma camera/CT imaging system on somatostatin receptor imaging of neuroendocrine tumours. Clin Radiol. 2006;61:579-587. 4. Howell DL, O'Dorisio MS. Management of neuroendocrine tumors in children, adolescents, and young adults. J Pediatr Hematol Oncol. 2012;34:S64-S68.