Neoadjuvant chemotherapy has been shown to increase the rate of breast conservation in clinical trials and small institutional series, but it has never been studied on a national level.

We performed a retrospective review of the National Cancer Database (NCDB). The NCDB is a joint project of the Commission on Cancer of the American College of Surgeons and the American Cancer Society and contains about 80% of the cancer cases in the United States. All women in the NCDB diagnosed with invasive breast cancer from 2006 through 2011, who underwent definitive breast surgery and received either neoadjuvant or adjuvant chemotherapy, excluding patients with distant metastases or T4 tumors, were included and rates of breast preservation were determined.

Of 354,204 patients who met the inclusion criteria, 59,063 (16.7%) underwent neoadjuvant chemotherapy. This proportion steadily increased from 13.9% in 2006 to 20.5% in 2011 (p < 0.001). Receipt of neoadjuvant chemotherapy was associated with larger tumor size (7% cT1, 25% cT2, and 58% cT3; p < 0.001), more advanced nodal disease (11% cN0, 39% cN1-3; p < 0.001), younger patient age (21% <50 years vs 14% >50 years; p < 0.001), higher tumor grade (18% grade 3, 15% grade 2, vs 12% grade 1; p < 0.001), and estrogen receptor (ER)-negative tumors (21% ER negative vs 15% ER postive; p < 0.001). Multivariate logistic regression showed that when adjusted for the above variables, patients with tumors larger than 3 cm undergoing neoadjuvant chemotherapy were more likely to receive breast preservation than those who opted for primary surgery (odds ratio 1.7, 95% CI 1.6 to 1.8).

Neoadjuvant chemotherapy increases breast preservation for patients with breast tumor size larger than 3 cm.