PIK3CA testing in HR+/HER2− metastatic breast cancer: assessing pathology laboratories capacity and needs

The management of hormone receptor-positive/HER2-negative (HR+/HER2-) metastatic breast cancer (MBC) relies on molecular testing to inform treatment decisions. PIK3CA mutations, present in ~40% of cases, represent a key predictive biomarker for PI3K-pathway-targeted therapies. Despite its clinical relevance, PIK3CA testing continues to face challenges related to laboratory organization, standardization, and access. We conducted a nationwide, cross-sectional survey to evaluate current practices and institutional readiness for PIK3CA testing in Italy, in the context of the anticipated expansion of PI3K-targeted therapies, including inavolisib. A total of 118 healthcare professionals from institutions across 15 regions participated, providing data on test availability, laboratory workflows, analytical methodologies, accreditation status, and implementation barriers. Descriptive statistics were used for analysis. Overall, 88.1% of institutions reported the ability to perform PIK3CA testing, with 57.6% offering on-site analysis. Testing was predominantly performed in pathology laboratories (76.5%), followed by molecular biology (16.2%) and genetics laboratories (7.4%). However, 46.6% of institutions lacked formal molecular accreditation, and ISO:15189 certification remained uncommon. Pre-analytical workflows relied mainly on formalin-fixed paraffin-embedded (FFPE) tissue samples (89.7%), with limited routine use of liquid biopsy. Next-generation sequencing (NGS) was the most frequently adopted analytical approach (45.6%), followed by combined NGS and PCR-based strategies (36.8%). Most institutions reported turnaround times of 7-15 days. In conclusion, this updated survey indicates progress in access to PIK3CA testing and consolidation of NGS-based methodologies in Italy. Nevertheless, persistent gaps in accreditation, heterogeneous workflows, and limited integration of liquid biopsy highlight ongoing challenges in standardization and diagnostic equity. Coordinated national strategies will be essential to ensure consistent, high-quality molecular diagnostics in HR+/HER2- MBC.