Small Intestine cancer questions

Do cancers of the small intestine behave similar or different depending on where in the small intestine they are: duodenum, jejunum or ileum?

In general all small bowel adenocarcinomas have similar biological behavior irrespective of anatomical site, except that localized duodenal cancers have more complicated surgical resection considerations.

What are the two main types of small intestinal cancers and is it important to know the difference?

Adenocarcinoma and neuroendocrine carcinoma. Yes critical to know the difference as these two tumors have very different biological behavior and prognosis.

Is immunotherapy approved for small intestinal adenocarcinoma?

No, it is not approved except for the subset of cancers that are deficient in mismatch repair (also called microsatellite instability high) or if the tumor mutation burden is greater than 10 mut/mb.