Surgical Axillary Staging Before Neoadjuvant Chemotherapy: Who Gets It and Why We Should Avoid It.

Background: Surgical axillary staging demonstrating positive nodal disease before neoadjuvant chemotherapy (NAC) necessitates axillary lymph node dissection (ALND) post-NAC. Despite evidence supporting post-NAC surgical staging, we hypothesized that there is persistent use of pre-NAC staging and that it is associated with aggressive clinicopathologic features and a higher rate of subsequent ALND.

Patients And Methods: Stage I-III breast cancer patients who underwent lymph node staging surgery and received NAC between 2013 and 2017 in the National Cancer Database were included. Sequence of staging surgery and chemotherapy administration was determined. Multivariable regression was used to assess characteristics associated with pre-NAC staging. Rate of ALND was compared between those who had pre- and post-NAC surgical axillary staging.

Results: In total, 120,538 met inclusion; 68% received NAC first and 32% had pre-NAC staging. Pre-NAC staging surgery was associated with younger age (age < 30 versus 40-49 years, HR 1.1) and decreased with older age (ages 70-79/80+ versus 40-49 years, HR 0.86 and 0.73). Advancing clinical T stage, lobular subtype, higher grade, and HR+/HER2- subtype were also associated with pre-NAC surgical staging. Women who underwent pre-NAC surgical staging were more likely to undergo ALND.

Conclusions: Over 30% of women underwent surgical axillary staging prior to NAC, resulting in higher rates of ALND in this cohort. While certain features suggestive of aggressive behavior (grade and T stage) were associated with pre-NAC surgical axillary staging, women with more aggressive tumor subtypes (triple negative/HER2+) were less likely to undergo pre-NAC surgical axillary staging. Pre-NAC surgical axillary staging should be performed only in rare circumstances to avoid unnecessary ALND.