Treatment of GIST and neuroendocrine GI tumors

1. Big picture

This topic contains two different surgical-oncology entities that are often confused:

GIST — gastrointestinal stromal tumor A mesenchymal tumour of the gastrointestinal tract, usually driven by KIT or PDGFRA mutations, treated mainly by complete surgical resection and tyrosine kinase inhibitors, especially imatinib.
GI neuroendocrine tumours — GI-NETs / carcinoid tumours Tumours arising from neuroendocrine cells of the GI tract, often slow-growing, sometimes hormone-producing, treated by site-specific resection, lymph node surgery, somatostatin analogues, liver-directed therapy, peptide receptor radionuclide therapy, and systemic treatment when advanced.

The key exam difference:

Feature	GIST	GI neuroendocrine tumour
Origin	Interstitial cells of Cajal / GI mesenchyme	Neuroendocrine cells of GI mucosa
Markers	KIT/CD117, DOG1, CD34 often positive	Chromogranin A, synaptophysin
Spread	Liver/peritoneum; lymph nodes uncommon	Lymph nodes and liver common
Main drug	Imatinib and other tyrosine kinase inhibitors	Octreotide/lanreotide ± PRRT/targeted therapy
Surgery	R0 resection, usually no lymphadenectomy	Resection often includes regional lymph nodes
Classic syndrome	Bleeding/mass effect

NCI notes that GISTs are most common in the stomach and small intestine and may arise from interstitial cells of Cajal, while GI neuroendocrine tumours form from hormone-producing neuroendocrine cells in the GI tract and most often occur in the small intestine, appendix, or rectum. ([Cancer.gov][1])

Treatment of GIST and neuroendocrine GI tumors

1. Big picture

PART I — GIST

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