Per NCCN Clinical Practice Guidelines In Oncology (NCCN Guidelines®), test for PIK3CA mutations as part of the initial MBC workup if all the following are true6:
✓ Patient has recurrent/Stage IV (M1) disease
✓ Tumor is HR+/HER2-
✓ Considering therapy with alpelisib + fulvestrant*
*Following progression on or after an endocrine-based regimen.