Small intestine cancer (small bowel cancer): overview, types and care

Anatomy and common tumour types

The small intestine is divided into duodenum, jejunum and ileum; tumours in the duodenum often have clinical and pathological features similar to stomach cancers, while those in the jejunum and ileum may resemble colorectal disease. Primary neoplasms encountered include:

• Adenocarcinoma — arises from glandular lining cells and is relatively common in the duodenum.
• Neuroendocrine tumours (carcinoids) — often slow growing and frequently encountered in the ileum.
• Lymphoma — originates in lymphoid tissue present in the small bowel.
• Gastrointestinal stromal tumours (GIST) and sarcomas — develop from connective tissue or smooth muscle.

Symptoms and diagnosis

Symptoms are often non‑specific: intermittent abdominal pain, unexplained weight loss, nausea, bleeding, anemia or bowel obstruction. Because early signs can mimic benign disorders, diagnosis commonly involves cross‑sectional imaging (CT or MRI), endoscopy with biopsy and, when indicated, capsule endoscopy or enteroscopy to view segments beyond standard reach.

Treatment and prognosis

Treatment depends on tumour type and stage. Surgery is the primary curative approach for localized lesions. For advanced disease, chemotherapy, targeted agents, immunotherapy and occasional radiotherapy are used according to histology. Prognosis varies: outcomes are generally better when disease is detected early, while advanced or metastatic tumours have a poorer outlook. Reported five‑year survival rates vary by study and tumour type.

Epidemiology, risk factors and research

Small bowel cancer is rare relative to other digestive‑tract malignancies. Recognized risk factors include chronic inflammatory conditions such as Crohn’s disease and celiac disease, inherited syndromes (for example familial polyposis or mismatch repair defects), prior abdominal radiation and some environmental exposures. Research priorities include improving early detection, tailoring systemic therapies to molecular subtypes and clarifying long‑term outcomes. For clinical context and further reading about the organ involved, see resources on the small intestine.