Abstract: The present disclosure relates to systems and methods for providing individualized prognostic assessments of breast cancer recurrence (e.g., locoregional recurrence). The systems and methods involve measuring gene expression from a patient sample to create a gene expression signature which identifies subjects who are not likely to benefit from radiotherapy following breast cancer surgery.

Abstract: Methods, systems, and kits for the diagnosis, prognosis, and treatment of breast cancer in a subject are disclosed. The invention also provides biomarkers and clinically useful genomic classifiers for identifying subjects at low risk of breast cancer recurrence who are likely to benefit from adjuvant radiotherapy. Further disclosed herein, in certain instances, are probe sets for use in detecting such biomarkers for determining the risk of breast cancer recurrence in a subject (e.g., locoregional recurrence). Methods of treating breast cancer based on expression profiling to determine the risk of breast cancer recurrence are also provided.