Guidance for Canadian Breast Cancer Practice: National Consensus Recommendations for the Systemic Treatment of...

Hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) early breast cancer (EBC) is the most common breast cancer subtype and encompasses a biologically heterogeneous group of tumours. Endocrine therapy (ET) remains the cornerstone of treatment, but decisions regarding chemotherapy, cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors, and bone-modifying agents must be tailored to tumour biology, clinical stage, and menopausal status. REAL Canadian Breast Cancer Alliance (REAL Alliance), a pan-Canadian group of breast cancer specialists, convened to develop national clinical consensus recommendations for the systemic management of HR+/HER2- EBC. Using a structured consensus process, 28 recommendations were endorsed, spanning neoadjuvant and adjuvant systemic therapy, surgical considerations, and use of bisphosphonates. Key recommendations include the selective use of neoadjuvant chemotherapy for high-risk or locally advanced disease; genomic testing to guide chemotherapy decisions, particularly in postmenopausal patients; ET as the foundation of adjuvant therapy with intensification using CDK4/6 inhibitors in higher-risk patients; and adjuvant bisphosphonates in postmenopausal women to reduce recurrence and improve survival. These consensus recommendations provide practical, evidence-based guidance to support individualized, patient-centred management of HR+/HER2- EBC in the Canadian context.