Breast cancer metastasis to the clavicle is usually caused by bloodstream metastasis of tumor cells. The main ways of cancer metastasis are hematogenous metastasis, lymphatic system metastasis, implantation metastasis and so on. Hematogenous metastasis means: cancer cells can enter into the blood circulation and metastasize to the corresponding location. For example, it is easy to lead to lung cancer: liver metastasis, adrenal gland metastasis, bone metastasis, brain metastasis can; it is easy to lead to breast cancer lung metastasis, liver metastasis, bone metastasis, etc.; therefore, there is a possibility that breast cancer can be metastasized to clavicle. If the patient has breast cancer metastasis to the clavicle, please consult the doctor in time, and MDT (multidisciplinary consultation) is mostly needed to draw up specific treatment plan. Early treatment can reduce the occurrence of complications, improve the quality of life and prolong the survival cycle.