Weekly paclitaxel and cisplatin as neoadjuvant chemotherapy with locally advanced breast cancer: a prospective, single arm, phase II study.

There was little evidence of weekly cisplatin regimen either for the locally advanced breast cancer or the metastatic setting. We aimed to evaluate that whether the combination of weekly paclitaxel and cisplatin could improve the efficacy of the neoadjuvant treatment for patients with locally advanced breast cancer. Patients with histologically confirmed large operable breast cancer received paclitaxel 80mg/m2 by weekly for 16 weeks and weekly cisplatin 25mg/m2 on day 1, 8 and 15, out of every 28 days for 4-week cycles. Trastuzumab was allowed for HER2-positive disease as weekly continuous regimen. The primary endpoint was locoregional total pathological complete response (tpCR) in breast and axilla lymph nodes after neoadjuvant treatment. One hundred and thirty-one patients were included in the study, among which 34.4% (45/131) patients achieved tpCR. Rate of pathological complete response (pCR) in the breast was 44.3% and the rate of near-pCR in breast was 48.1%. A significantly higher proportion of tpCR was seen in patients with triple negative breast cancer (64.7%, p = 0.003) and HER2 positive (non-luminal) cancer (52.4%, p = 0.018) compared with those who had luminal type tumors (24.7%). At multivariate analysis, negative estrogen receptor and high ki67 level independently predicted a better response. The most frequent toxicities were anemia, leukopenia and peripheral sensory neuropathy. Neoadjuvant chemotherapy by weekly paclitaxel and cisplatin combination was highly effective and tolerated in this study, especially in the triple negative and HER2 positive tumors.