This study will evaluate the efficacy and safety of antharcycline-based adjuvant chemotherapy compared with observation in triple negative breast cancer (TNBC) patients with residual invasive disease after platinum and taxanes based neoadjuvant chemotherapy.

This study is a multi-center, randomized, phase II study. TNBC patients with residual invasive disease (invasive breast tumor size≥1cm and/or positive axillary lymph nodes) after platinum and taxanes based neoadjuvant chemotherapy are enrolled (n = 286). Patients are assigned to the chemotherapy group or the observation group at a 1:1 ratio randomly 4-6 weeks after surgery. Patients in the chemotherapy group are given anthracycline combined with cyclophosphamide regimen for 4 cycles. At the same time, the blood and tissue samples are collected for relevant tests. Follow up every 3-6 months and record recurrences and deaths.

Inclusion Criteria:

• Patients with histologically confirmed invasive adenocarcinoma of the breast.
• Triple negative breast cancer: hormone receptor negative (ER < 10% and PgR < 10%) and HER2 negative (IHC 0/1+ or ISH non-amplified), as defined by the local pathology laboratory.
• Clinical stage at presentation: T1-4, N0-3, M0, with indications for neoadjuvant chemotherapy.
• Patient must have received platinum and taxanes neoadjuvant chemotherapy for at least 4 cycles and no tumor progression occurred.
• Patients should have undergone adequate tumor excision in the breast and lymph nodes after neoadjuvant chemotherapy.
• Residual invasive disease must be ≥1cm in the breast, and/or have positive axillary lymph nodes observed on pathologic exam after neoadjuvant chemotherapy.
• ECOG Performance Status: 0-1.
• Patients without severe heart, lung, liver and kidney disease.
• Adequate hematologic and end-organ function.
• No more than 6 weeks may elapse between definitive breast surgery and randomization.

Exclusion Criteria:

• Previous neoadjuvant chemotherapy with anthracycline or other drugs (except platinum and taxanes).
• Previous neoadjuvant chemotherapy with platinum or taxanes alone.
• Patients have received other adjuvant therapy.
• Comprehensive medical examinations have revealed distant metastases before randomization.
• Patients who are not suitable for anthracycline evaluated by investigators.
• Prior history of other malignancy (except carcinoma in situ).