Sentinel lymph node biopsy after neoadjuvant treatment in breast cancer: Work in progress.

Sentinel lymph node biopsy has replaced axillary lymph node dissection (ALND) in those patients with clinically node negative axilla and nowadays, patients with low burden disease in the SLNs may spare an ALND without compromising their oncologic outcomes. In the last decade, indications of neoadjuvant treatment (NAT) have been extended to patients with operable disease and with the use of targeted therapies, rates of pathologic complete response (pCR) after NAT have increased. In the neoadjuvant setting, SLN after NAT is feasible and accurate in clinically node negative patients and it has been explored in different randomized prospective studies in patients with clinically positive axilla in the continuous effort to avoid the morbidity of ALND. The importance of identifying patients with residual axillary disease may serve not only as indicator for selecting patients with pCR to be spared an ALND but also for selecting patients for additional therapy. Future research is needed to more accurately identify residual axillary disease and the SLN after NAT is the driver for this achievement.