Breast cancer is divided into five stages, that is, from stage 0-IV. In general, the lower the number, the less the cancer has spread, and the higher the number, for example, when it reaches stage IV, it means that the cancer has spread very extensively and belongs to advanced stage. In the same stage, there are some sub-stages, such as stage IVa and stage IVb. The earlier letter represents the lower stage, for example, stage IVa has slightly better symptoms than stage IVb. This staging is based on the size of the tumor, lymph node metastasis, and whether there is metastasis to distant organs, which is a standard TNM staging. Different combinations of TNM constitute different stages of breast cancer. It is specifically judged in detail based on the postoperative pathology of breast cancer and combined with whole body imaging.