HER-2 directed therapies across gastrointestinal tract cancers – A new frontier.

• Precision medicine in gastrointestinal cancers is lagging compared to other cancers. • HER-2 is an emerging treatment target for gastrointestinal cancers. • Timing and method of testing HER-2 in gastrointestinal cancers needs optimization. Gastrointestinal (GI) cancers are common and in the metastatic setting they have a poor prognosis. The current mainstay of treatment of GI cancers is chemotherapy; however, the biomarker-directed treatment landscape is evolving. HER-2 is overexpressed in a portion of GI cancers and is an emerging target for therapy, with recent FDA tumor agnostic approval for trastuzumab deruxtecan. Testing for HER-2 expression is not standardized across GI cancers, methodology requires further optimization and standardization as HER-2 targeted therapy emerges into the treatment landscape. There is established rationale for use of HER-2 targeted therapy in first line treatment of metastatic gastric cancer, and emerging evidence with variable benefit in bile duct, pancreatic and colorectal cancers. [ABSTRACT FROM AUTHOR]