• Adenocarcinoma (majority of cases, >= 50%)
• Lymphoma (uncommon) usually non-Hodgkin’s type
• Sarcoma (most commonly leiomyosarcoma and more rarely, angiosarcoma or liposarcoma)
• Carcinoid (20% of SI tumours)
• GIST

Benign lesions like adenomas, leiomyomas, fibromas, and lipomas may also arise in the small bowel.

What are the clinical features of SI cancers?

They may present with abdominal pain, obstruction, and bleeding or weight loss.

Discuss investigations for SI cancers?

• Endoscopy- OGD, enteroscopy, wireless capsule endoscopy
• CT scan
• Small bowel enteroclysis

Discuss treatment of SI neoplasms?

The predominant modality of treatment is surgery when resection is possible, and cure relates to the ability to completely resect the cancer.

• Adenocarcinoma of SI
• Wide segmental resection for localized adenocarcinomas of the small bowel. Role of adjuvant therapy is undefined. Chemotherapy may be offered for node positive disease
• For unresectable primary disease- surgical bypass of the obstructing lesion may be needed. Palliative radiotherapy is also an option
• SI lymphoma- the treatment approach is similar to the histological subtype of lymphoma arising in nodal regions.

What is the prognosis?

• In general, five-year survival rates for small bowel adenocarcinoma are worse than for similarly staged colon cancers.
• 5-year cancer-specific survival for node-positive small bowel adenocarcinoma is between 12 and 35 percent
• The 5-year survival rate for resectable leiomyosarcoma, the most common primary sarcoma of the small intestine, is approximately 50%.