Expert recommendations for PIK3CA testing in HR+/HER2- locally advanced and metastatic breast cancer.

PIK3CA mutations are common in HR+/HER2- metastatic breast cancer and guide the use of PI3K-targeted therapies. This expert consensus provides recommendations on timing, methods, and interpretation of PIK3CA testing, emphasizing early assessment at metastatic diagnosis, preferred use of NGS panels, and standardized pre-analytical workflows. Reflex and dual-sample strategies can reduce delays and failures. Implementation requires coordinated logistics, education across the diagnostic chain, and equitable access to ensure timely, personalized treatment.