At the Speed of SOUND: The Pace of Change for Axillary Management in Breast Cancer

Excerpt

Just when we thought axillary management for patients with breast cancer had reached a peak of convolution, new data come to the horizon. Starting in the early 20th century, historical surgical dogma prioritized pathologic nodal status, as this was the guiding force behind adjuvant systemic therapy and radiation therapy recommendations. Despite the lack of survival benefit of axillary lymph node dissection (ALND) being demonstrated in NSABP B-04 in the 1970s,¹ a true understanding of tumor biology was in its infancy and nodal status was necessary for both prognostication and treatment planning. Development and validation of the sentinel lymph node biopsy (SLNB) allowed for de-escalation of surgical nodal staging in clinically node-negative women following publication of NSABP B-32 in the 1990s,² but ALND remained the mainstay for both clinically and pathologically node-positive patients. As our understanding of the morbidity of ALND evolved, its need in patients with low nodal disease burden was questioned and disproven with ACOSOG Z0011 and AMAROS in the 2010s,^3,4 forever changing the landscape of surgical axillary management in breast cancer. The advent of molecular genomic testing further minimized the importance of pathologic nodal status with publication of the RxPONDER trial, illustrating how Oncotype DX testing can be used, even in the node-positive postmenopausal patient, to determine the benefit of chemotherapy.⁵ With this knowledge, as well as improvements in breast imaging and expansion of systemic therapy options, the natural next question became ‘do we even need surgical nodal staging?’ Enter the SOUND (Sentinel Node vs. Observation after axillary UltraSound) trial.⁶ …