Abstract
Appendiceal Adenocarcinoma (AA) is a rare gastrointestinal cancer with no FDA-approved targeted therapies. Here, we retrospectively compare BRAF-mutant AA and colorectal cancer (CRC). BRAF mutation is rare in AA (3%). Unlike CRC, BRAF(V600E) AA is not associated with poor prognosis, female sex, microsatellite instability, mucinous histology, or poor differentiation. In both cancers, BRAF(V600E) but not atypical BRAF mutations are mutually exclusive with other Ras-activating mutations. BRAF(V600E) + EGFR inhibition shows efficacy in BRAF(V600E) AA (disease control rate = 80%, median progression-free survival = 7.1 months).