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9 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Small intestinal neuroendocrine tumours are slow-growing hormone-producing tumours of the ileum and jejunum, often found only after they have spread to lymph nodes and the liver. Monthly somatostatin analogue injections control symptoms and growth, lutetium-177 dotatate is the main second treatment, and everolimus, cabozantinib and surgery fill in.
Small intestinal neuroendocrine tumours arise from enterochromaffin cells of the distal jejunum and ileum, are often multiple along the same segment, and stay small while their mesenteric node metastases and the fibrosis around them grow large enough to kink the bowel and its blood supply. Most are well differentiated with a low Ki-67 index, nearly all express somatostatin receptor 2, and about a fifth to a third of patients with liver metastases develop carcinoid syndrome from serotonin that escapes the liver's first-pass clearance; years of exposure can scar the right-sided heart valves. Diagnosis rests on somatostatin receptor PET, chromogranin A and 24-hour urinary 5-HIAA, and the grade is read from Ki-67 and mitotic count on biopsy.
The treatment sequence was built by a short chain of trials. PROMID (Journal of Clinical Oncology 2009) randomised 85 patients with treatment-naive metastatic midgut tumours to octreotide LAR or placebo and lengthened time to progression from 6.0 to 14.3 months, the first proof that a somatostatin analogue slows growth as well as symptoms; CLARINET (New England Journal of Medicine 2014) did the same for lanreotide across enteropancreatic tumours, with the median progression-free survival not reached against 18.0 months on placebo. NETTER-1 (New England Journal of Medicine 2017) then randomised 231 patients with midgut tumours progressing on octreotide to lutetium-177 dotatate with octreotide or to high-dose octreotide; 65.2 percent against 10.8 percent were progression-free at 20 months, responses rose from 3 to 18 percent, and the final analysis gave median overall survival of 48.0 against 36.3 months, a difference that did not reach statistical significance because of crossover. Lutathera was approved in 2018, and NETTER-2 (Lancet 2024) moved it to first line for grade 2 and 3 tumours with a Ki-67 of 10 percent or more, lengthening progression-free survival from 8.5 to 22.8 months. Everolimus earned its gut indication in RADIANT-4 (Lancet 2016), where progression-free survival was 11.0 against 3.9 months in non-functional lung and gastrointestinal tumours, and cabozantinib was approved in 2025 after the extra-pancreatic cohort of CABINET (New England Journal of Medicine 2024) showed 8.4 against 3.9 months.
| Setting | Approach | Guideline |
|---|---|---|
| Diagnosis and staging | Biopsy with Ki-67 grading, somatostatin receptor PET, cross-sectional imaging of the liver, chromogranin A and urinary 5-HIAA, echocardiography if carcinoid syndrome is present. | not mapped |
| Localised or resectable disease | Segmental small bowel resection with mesenteric lymphadenectomy, inspecting the whole small bowel for further primaries; the primary is often removed even when liver metastases are present. | not mapped |
| Advanced, first line | Octreotide LAR or lanreotide (PROMID, CLARINET); lutetium-177 dotatate first line for grade 2 to 3 tumours with a Ki-67 of 10 percent or more (NETTER-2). | not mapped |
| Progression on a somatostatin analogue | Lutetium-177 dotatate (NETTER-1); everolimus (RADIANT-4); cabozantinib (CABINET); liver-directed therapy for hepatic-dominant disease. | not mapped |
| Carcinoid syndrome | Somatostatin analogue dose escalation, telotristat ethyl for refractory diarrhoea, octreotide infusion around procedures to prevent carcinoid crisis, valve surgery for carcinoid heart disease. | not mapped |
| After radioligand therapy | Everolimus or cabozantinib; 177Lu-edotreotide if approved; alpha-emitting radioligands and retreatment in trials. | not mapped |