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10 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.
Cancers of the small intestine are rare and often found late because the small bowel is hard to see and symptoms are vague. Surgery cures early disease, chemotherapy borrowed from bowel cancer helps after surgery and in advanced disease, and a large minority of tumours have a repair defect that makes them respond well to immunotherapy.
Small bowel adenocarcinoma (SBA) is the epithelial cancer of the duodenum, jejunum and ileum; the small intestine also gives rise to neuroendocrine tumours (the most common small bowel malignancy in some registries), gastrointestinal stromal tumours and lymphoma, each covered on their own pages. Risk factors for SBA are inflammatory and hereditary: Crohn's disease (ileal tumours), coeliac disease (jejunal tumours, often MSI-high), Lynch syndrome, familial adenomatous polyposis (duodenal and periampullary tumours) and Peutz-Jeghers syndrome. Molecularly, SBA sits between colorectal and gastric cancer: KRAS and TP53 mutations are common, APC mutation is less common than in colon cancer, and mismatch-repair deficiency is found in a larger share than in colorectal cancer, with a further subset carrying HER2 amplification or ERBB2 mutations.
Segmental resection with regional lymphadenectomy (pancreatoduodenectomy for duodenal tumours) is the curative treatment. Adjuvant chemotherapy has been extrapolated from colorectal cancer; the international BALLAD trial (NCT02502370) is the first randomised test of adjuvant fluoropyrimidine with or without oxaliplatin versus observation in stage I to III disease. For advanced disease, CAPOX or FOLFOX is first line; pembrolizumab is the first-line choice for MSI-high or mismatch-repair-deficient tumours, where response rates are high and durable. The NCCN small bowel adenocarcinoma guideline (2019 onwards) and the ASCO 2024 guideline now give the disease its own recommendations rather than a footnote in the colon guideline.
| Setting | Approach | Guideline |
|---|---|---|
| Localised | Segmental resection with en bloc lymphadenectomy; pancreatoduodenectomy for duodenal tumours not amenable to segmental resection. | NCCN Category 2A |
| Adjuvant (stage III; selected stage II) | Fluoropyrimidine with oxaliplatin (CAPOX or FOLFOX) for six months, extrapolated from colon cancer; BALLAD is the randomised test. | NCCN Category 2A |
| Advanced, MSI-high / dMMR | Pembrolizumab first line (tumour-agnostic approval; ZEBRA and KEYNOTE-158 cohorts). | NCCN Category 2A (preferred) |
| Advanced, MSS | CAPOX or FOLFOX first line; taxane- or irinotecan-based second line; HER2-directed therapy in trials; clinical trial enrolment encouraged. | not mapped |