Low risk: 1) negative axillary lymph nodes; 2) lesion size <2 cm in the specimen; 3) histological grade I; 4) no tumor invasion in the perineural vasculature; 5) no overexpression or amplification of Her-2 gene; 6) age ≥35 years. Moderate risk: 1, negative axillary lymph nodes with at least one of the following: 1) lesion size ≥ 2 cm in the specimen; 2) histologic grade 2-3; 3) perineural vascular tumor invasion; 4) Her-2 gene overexpression or amplification; 5) age ≤ 35 years; 2, 1-3 metastases in axillary lymph nodes without Her-2 gene overexpression or amplification. High risk: 1, 1-3 metastases in axillary lymph nodes with Her-2 gene overexpression or amplification; 2, 4 or more metastases in axillary lymph nodes.