Analysis of the factors affecting pathologic complete response to neoadjuvant chemotherapy in breast cancer patients

Abstract

To analyze the factors affecting pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) in breast cancer patients. A retrospective cohort study was carried out to analyze the clinical data of 141 breast cancer patients treated with neoadjuvant chemotherapy. The factors affecting pCR and the changes of tumor receptor status before and after treatment were analyzed. Among all the 141 patients, 21 patients (14.9%) achieved pCR. The rate of pCR achieved by regimens of anthracycline combined with taxane was higher (16.8%, 19/113) than that by anthracycline-containing regimens (7.1%, 1/14). The dose intensity of anthracycline had a significant correlation with pCR rate (P < 0.05). The pCR rate in the relative dose intensity of taxane ≥ 0.85 arm was higher than that of < 0.85 arm (P = 0.02). Eighty patients (56.7%) had completed more than 4 cycles of chemotherapy and the median time to achieve pCR was 6 (3 to 10) cycles. The pCR rate had a significant difference between patients < 6 and ≥ 6 cycles (7.1% vs. 22.5%,P = 0.01). Multivariate analysis showed that tumor size measured by palpation ≤ 5 cm and ≥ 6 chemotherapy cycles were significantly related with pCR rate (P < 0.05). In all the 21 pCR patients, the pre-treatment ER(-), PR(-), HER-2(-) statuses were in 14, 14 and 17 patients, respectively. The status of ER, PR, HER-2 of most patients (74.2%, 69.7% and 87.7%, respectively) was not changed after treatment. Among the patients with changes in receptor status, ER changed from negative to positive was in the majority (37.1%, 13/35 vs. 12.9%, 4/31, P < 0.05), and the percentage of changes in PR and HER-2 status had no significant differences. The regimens of anthracycline combined with taxane can achieve a higher pCR rate. The lymph node and receptor status before therapy have no significant correlation with pCR. Patients who have primary tumor size ≤ 5 cm, ≥ 6 chemotherapy cycles and enough dose intensity are easier to achieve pCR. The receptor status before and after therapy should be determined, and according to any positive results, physicians can chose HER-2 targeted therapy and/or endocrine therapy after surgery to benefit the patients.