Changing Local Therapy in Breast Cancer: Who Needs What, and When?

The local therapy of breast cancer continues to evolve toward less surgery. Breast conservation is firmly in place, with recent trends toward decreased rates of re-excision. Axillary dissection is becoming a rare operation and is being replaced by sentinel node biopsy. The switch to sentinel node biopsy occurred first in patients with pathologically tumor-free nodes, and later in patients with limited nodal disease. Sentinel node biopsy is now also widely used in patients with pathologically positive nodes who receive neoadjuvant chemotherapy. Axillary surgery is being replaced with radiotherapy in some situations, and ongoing trials will further clarify the need for nodal radiotherapy in specific situations following neoadjuvant systemic therapy. Shorter radiotherapy regimens are widely accepted as the standard of care following breast conservation, and the omission of radiotherapy is recognized as appropriate for older patients. The appropriate sequencing of specific components of local therapy, particularly with regard to the timing of chemotherapy, requires thoughtful multidisciplinary planning and leveraging of the strengths of each component of therapy. Here, we review issues related to therapeutic sequencing and decision making in the local therapy of breast cancer.