Abstract
Breast cancer has a complex biology with heterogeneous treatment approaches that have changed significantly over the last two decades. The MAGIC survey provides valuable insight into worldwide treatment recommendations for early breast cancer patients and the clinical and pathologic criteria used for these decisions. The overall findings indicate that there is substantial heterogeneity in how patients are treated and a substantial uncertainty in treatment recommendations for a large proportion of patients, highlighting an unmet need for broadly available markers, such as multigene assays, that can help to make more informed treatment decisions by predicting a patient's likelihood of benefit from adjuvant chemotherapy.