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

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).

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.

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.

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.