Small Bowel Adenocarcinoma: Etiology, Presentation, and Molecular Alterations.

Small bowel adenocarcinoma (SBA) is a rare cancer that has been treated similarly to colorectal cancer (CRC) in the advanced setting. Incidence has been increasing as detection efforts have been improving for these challenging-to-diagnose tumors, but patients frequently experience prolonged nonspecific symptoms due to delayed diagnosis. As a result of such delays and likely due to variant biology, patient outcomes for SBA are inferior to those for CRC at all stages of diagnosis. Recent molecular studies highlight the genomic differences underpinning these tumors and suggest new future pathways for treatment, distinct from CRC.