Breast surgery after neoadjuvant therapy

The standard of care in breast surgery has changed, from mastectomy to breast conserving surgery whenever possible, and from axillary dissection to sentinel node biopsy. Neoadjuvant systemic approaches have broadened the indications for organ-conserving and less mutilating surgery, but also raise important questions of balancing locoregional treatment de-escalation and protecting excellent long-term outcomes.

Recent studies have aimed at investigating the safety of de-escalating surgical approaches not only in the upfront breast surgery situation but also after neoadjuvant systemic therapy. This pertains to both the safety of breast conserving surgery - including more complex oncoplastic approaches - within the new (posttherapeutic) anatomical extent of the residual disease, but more controversially to de-escalating surgical treatment of the axilla. While sentinel node biopsy appears to be the standard of care for node-negative disease also after primary systemic therapy, the optimal procedure in situations of posttherapeutic node-positive disease remains highly controversial.

Both breast and axillary surgery after neoadjuvant systemic therapy for women with breast cancer has undergone multiple paradigm changes in recent years. For the primary tumor in the breast, breast-conserving surgery constitutes the standard of care, and unnecessary mastectomies should be strongly discouraged. For axillary surgery, sentinel-node biopsy should be aimed at, and completion axillary dissections minimized for situations of extensive disease and or poor neoadjuvant treatment response. Additional techniques such as targeted axillary dissection are currently under evaluation in clinical trials.