Historically, prognosis and treatment decision making for breast cancer patients have been
dictated by the anatomic extent of tumor spread. However, in recent years,“breast cancer”
has proven to be a collection of unique phenotypes with distinct prognoses, patterns of
failure, and treatment responses. Recent advances in biologically based assays and
targeted therapies designed to exploit these unique phenotypes have profoundly altered
systemic therapy practice patterns and treatment outcomes. Data associating locoregional …