Axillary dissection versus no axillary dissection in patients with sentinel-node micrometastases: commentary on the IBCSG 23-01 Trial

Breast surgical oncologists have rapidly and successfully transitioned from the routine use of axillary lymph node dissection (ALND) to sentinel lymph node (SLN) biopsy for staging the axilla in clinically node negative patients. This approach limits the use of ALND to those patients with pathologically-proven axillary lymph node metastases and has prompted great current interest in whether or not all SLN-positive patients benefit from a completion ALND. Analysis of population-based data shows a decades-long trend towards omitting ALND in patients with low volume axillary disease. Thus, even prior to publication of the results of the ACOSOG Z0011 study and the IBCSG 23-01 study, completion ALND was being performed less frequently for selected patients with nodal micrometastases. Herein we review the contribution of the recently published IBCSG 23-01 study which provides additional data to confirm that for selected patients, mainly those with small, estrogen receptor-positive tumors with low nodal disease burden undergoing breast conservation with radiation and adjuvant systemic therapy, ALND might be avoided safely. This trial, which included small numbers of patients treated by mastectomy without radiation, and lumpectomy with partial breast irradiation, suggests interest in further clinical trials investigating these important patient populations. The study’s short median follow-up however, cautions us to be clear in discussion, especially with younger patients who have otherwise biologically favorable tumors, that the long-term outcomes of SLN biopsy alone for low volume axillary disease remains unknown.