Survival outcomes of neoadjuvant chemotherapy with zoledronic acid for HER2-negative breast cancer

Abstract

Background: A randomized phase 2 trial in women with HER2-negative breast cancer has shown that adding zoledronic acid (ZOL) to neoadjuvant chemotherapy (CT) has potential anticancer benefits in postmenopausal and triple-negative (TN) breast cancer patients. We report the data for the secondary end point of disease-free survival (DFS).

Methods: Patients were randomly assigned to receive CT or CT + ZOL (CT-Z). All patients received four cycles of FEC100 followed by 12 cycles of paclitaxel weekly. ZOL (4 mg) was administered 3-4 times weekly for 7 wk to the CT-Z group patients. The primary end point was pathologic complete response (pCR). The secondary end points were the clinical response rates, rate of breast-conserving surgery, safety, and DFS.

Results: Of the 188 patients enrolled, 95 were assigned to the CT group and 93 to the CT-Z group. DFS and overall survival were analyzed in 92 and 88 patients with the mean times of 5.15 y and 5.38 y, respectively. The 3-y DFS rate was 84.6% in the CT group and 90.8% in the CT-Z group (P = 0.188). The particular benefit from ZOL for the neoadjuvant CT seen as improvement of the pCR rate was indicated in the 3-y DFS period for TN cancer cases (CT versus CT-Z: 70.6% versus 94.1%) but not for postmenopausal cases.

Conclusions: ZOL did not improve DFS when combined with CT. However, the improvement of the pCR rate translated to survival outcomes in TN breast cancer. The short-term application of ZOL may not be sufficient to improve the outcome in postmenopausal patients.

Keywords: Disease-free survival; HER2-negative breast cancer; Neoadjuvant chemotherapy; Zoledronic acid.