Neoadjuvant chemotherapy (NAC) represents the standard treatment for patients with locally advanced breast cancer. We evaluated the tumor response and clinical outcomes according to molecular subtypes in locally advanced breast cancer, and we sought to investigate the benefit of NAC among luminal HER2(-) type
Our study evaluated data of 3,452 patients who were operated with malignant breast cancer between January 2010 and December 2016. We retrieved prospectively collected data of 249 patients with cytological node-positive breast cancer who were treated with NAC and underwent axillary lymph node dissection (ALND). Expression of estrogen receptor (ER), progesterone receptor (PgR), HER2, and Ki67 were used to divide into 4 subtypes: luminal HER2(-) (ER+, PR+, HER2-), luminal HER2(+) (ER+ and/or PR+, HER2+), HER2-overexpression (ER-, PR- and HER2+) and triple-negative (ER-, PR-, and HER2-). We determined rates of breast-conserving surgery, axillary pCR and tumor response rate after chemotherapy by approximated biologic subtype
Axillary pCR was achieved for 79 patients (32.4%) who underwent ALND after NAC in our study. The axillary pathologic complete remission (pCR) rates according to different subtypes are as follows: luminal HER(-), 26 of 114 (22.8%), luminal HER(+), 14 of 39 (35.9%), HER2-overexpression 19 of 44 (43.2%), and triple-negative, 20 of 47 (42.6%) (p = 0.023). Rates of breast-conserving conversion were not significantly different in patients with luminal HER2(-) (11.4%) than other tumor subtype (p = 0.833). The median tumor response rate was 47.1% for the 249 Patients. The clinical tumor response rate of the breast tumor and axillary LN after NAC was not significantly different in the patients with luminal HER2(-), compared with the patients with other tumor subtype(p = 0.343).
While axillary pCR is significantly less common among women with luminal HER2(-) type, these patients still benefit from NAC in the aspect of increasing tumor response rate and breast conservation rate.
Clinical trial identification
Legal entity responsible for the study
Kim Hyung Suk
All authors have declared no conflicts of interest.