This study is a multi-center, randomized, phase II study. TNBC patients with residual invasive disease (invasive breast tumor size1cm 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.

