( 1) Definition of low risk: negative axillary lymph nodes with all of the following characteristics: lesion size (pT) ≤ 2 cm in the specimen, pathological grade 1, no invasion of peripheral tumor vessels, HER -2 (-), age > 35 years. Chemotherapy regimen can be chosen: CMF *6 or AC / EC*( 4-6). ( 2) Definition of moderate risk: ① Negative axillary lymph nodes with at least one of the following characteristics: lesion size (pT) > 2 cm in the specimen, pathological grading of grade 2 – 3, invasion of tumor peripheral vessels, HER-2 gene overexpression or amplification, and age < 35 years. ② Axillary lymph node micrometastasis (LNM) 1-3 and HER-2 (-). The option is FAC/FEC *6. ( 3) Definition of high risk: ① Axillary lymph node micrometastasis (LNM) 1-3 and HER-2 (+); ② Axillary LNM > 3. The options of chemotherapy are: AC-T (AC sequential paclitaxel), FEC x 3-T x3 (FEC sequential doxorubicin), TAC (doxorubicin bing doxorubicin/cyclophospholipid) ), and A toC. It is also possible to use biweekly dose intensive chemotherapy with G-CSF support, ddAC x4 * ddT x4; or ddA * ddT-ddC (doxorubicin sequential to paclitaxel sequential to cyclophthalamide).