Abstract
Background
Neoadjuvant chemotherapy (NAC) can downstage the axilla for patients with breast cancer and spare axillary lymph node dissection (ALND). Although tumor biomarkers help predict response to NAC and inform surgical decision-making, the role of Ki-67 in predicting axillary pathologic complete response (pCR) and recurrence is unclear.Methods
Consecutive patients with stage II/III node-positive breast cancer treated with NAC from January 2007 to July 2021 were identified from a prospective database. Ki-67 was categorized. Multivariable logistic regression identified predictors of nodal pCR and recurrence. Distant disease-free survival (DDFS) analysis was performed for changes in Ki-67 for patients with residual disease.Results
Of 407 node-positive patients treated with NAC, 172 (42.3%) converted to ycN0. Most patients had cT2 (52.9%) and cN1 disease (90.1%). Median Ki-67 from the biopsy specimen was 43% (interquartile range 31-70); Ki-67 was highest in triple-negative disease. Overall, 105 patients (61.0%) had a nodal pCR; the rate of nodal pCR was significantly different among biomarker subtypes: 32.8% for hormone receptor-positive (HR+ )/human epidermal growth factor receptor 2-negative (HER2-), 73.3% for HR-/HER2-, 75.0% for HR+/HER2+, and 81.8% for HR-/HER2+ (p Conclusions
Ki-67 was not predictive of nodal pCR and is not a useful adjunct for surgical decision-making; however, a decrease in Ki-67 from biopsy to surgical specimen may suggest improved DDFS.