National Trends in the Use of Neoadjuvant Chemotherapy for Hormone Receptor-Negative Breast Cancer: A National Cancer Data Base Study

Background: Neoadjuvant chemotherapy (NAC) downstages tumor size and nodal disease. This study evaluates national practice patterns of NAC use in hormone receptor-negative breast cancer. Methods: We identified patients in the National Cancer Data Base (NCDB) with hormone receptor-negative invasive breast cancer (2004–2012). Univariate and multivariable logistic regression was used to assess associations and trends across time. Results: Of 171,985 patients, 130,723 (76.0%) received chemotherapy and 41,262 (24.0%) did not. Chemotherapy use was higher in young patients and higher T- and N-stage disease (all p < 0.001). Of those patients treated with chemotherapy, 23,165 (17.7%) received NAC and 107,558 (82.3%) received adjuvant chemotherapy (AC). NAC use increased from 2004 to 2012 (13.0–23.5%; adjusted odds ratio [aOR] 1.42; p < 0.001). Higher clinical T stage (ORs 3.63, 11.81, and 22.34 for cT2, cT3, and cT4a–c, respectively, vs. cT1) and cN+ disease (OR 2.86) [each p < 0.001] were associated with NAC, as were younger patient age and better Charlson–Deyo comorbidity score. Furthermore, BCS rate was higher in the NAC group in cT2 and cT3 tumors (aOR 1.17 and 1.45, respectively; both p < 0.001). In patients with cN+ disease, NAC converted 43.7% to pN0. Less extensive axillary surgery (one to five nodes removed) was more likely in cN+ patients treated with NAC (aOR 1.66; p < 0.001). Conclusions: In hormone receptor-negative breast cancer, chemotherapy was mostly administered adjuvantly, but neoadjuvant use increased over time and was more likely in younger patients and higher T- and N-stage disease. Node-positive patients treated with NAC were less likely to have pathologically positive nodes and more likely to have less extensive axillary surgery.