Molecular subtypes as a predictor of response to neoadjuvant chemotherapy in breast cancer patients

The objective of this study was to assess response to neoadjuvant chemotherapy in molecular subtypes of breast cancer.

This study included 60 patients with locally advanced and metastatic breast cancer. The authors excluded patients who already underwent mastectomy or were given any chemotherapy/radiotherapy. They analyzed the clinical and immunohistochemical characteristics using core biopsy specimens to determine their correlations with response to chemotherapy.

A clinical complete response was observed in 19 patients (31.7%), a clinical partial response in 30 patients (50%), clinical stable disease in 8 patients (13.3%), and progressive disease in 3 patients (5%). A pathologic complete response (pCR) was observed in 7 (21.87%) of 32 patients who underwent surgery. High Ki-67 was associated with human epidermal growth factor receptor 2 (HER2)-positive status (P = 0.027) and triple-negative breast cancer (TNBC) (P = 0.006). Multiple logistic regression analysis showed that pCR was correlated with HER2 status (odds ratio 26.589, confidence interval [CI] =1.606-44.190), P = 0.022. Of the seven patients found to have pCR, six patients (85.7%) were treated with taxol-containing regimen. The other parameters that were correlated with pCR are TNBC and estrogen receptor/progesterone receptor status. Tumor size, Ki-67 value, and grade of the tumor were not correlated with clinical response.

Molecular subtype in breast cancer is an effective factor for predicting response to neoadjuvant chemotherapy. HER2-positive status was associated with high Ki-67 and high clinical and pathological response rate. Taxol needs to be added in neoadjuvant chemotherapy to improve pCR. Luminal subtypes respond poorly to chemotherapy.