Neoadjuvant Chemotherapy in early-stage breast cancer: the trend over time and the impact on axillary management, A National Cancer Database Analysis

Background: Despite several benefits to neoadjuvant chemotherapy (NAC), there are uncertainties about NAC utilization in early breast cancer. Methods: We performed a retrospective analysis of the National Cancer Database (NCDB), selecting cN0, cT1-2, M0 breast cancers who received chemotherapy between 2010 and 2021. Axillary lymph node dissection candidacy (ALNDC) was considered positive in the NAC group if any positive nodes were recorded, and in the AC group if more than two positive nodes were documented after surgery. The trend of NAC use and pathologic complete response (pCR) rate over time was assessed. ALNDC was compared between NAC and adjuvant chemotherapy (AC), stratified by stage and phenotype. Results: In a cohort of 295,110 patients, NAC was administered in 13%, increasing from 6% in 2010 to 22% in 2021. While 36% achieved pCR, increasing from 16% in 2010 to 46% in 2021. ALNDC was observed in 9.6% of the NAC and 9.7% of the AC groups (p = 0.2). NAC increased ALNDC in stage I patients (10% vs 8%, p<0.001). However, NAC decreased ALNDC in stage II patients (9% vs. 13%, p < 0.001). NAC increased the rate of ALNDC in hormone-receptor-positive (HR+) (24% vs 13%, p<0.001). However, it decreased ALNDC in HER2+ patients (5% vs 6%, p = 0.004). In the adjusted multivariable analysis, NAC increased the ALNDC (OR: 2.5, 95% CI 2.4-2.6; p < 0.001). Conclusion: Despite the undeniable benefits of NAC, our results revealed an increase in ALNDC in HR+ and stage I breast cancer patients and a decrease in ALNDC in HER2+ patients compared to the AC group. This reinforces the importance of selecting the right treatment for the right patient at the right time.