Bone metastasis in breast cancer patients may not have obvious clinical symptoms if it has not metastasized to the arm; if bone metastasis has metastasized to the arm, clinical symptoms such as pain in the bone, difficulty in movement, numbness in the limbs and pathologic fracture may appear. 1. No metastasis to the arm: if the bone metastasis of breast cancer patients has not metastasized to the arm, it will not cause compression to the local nerves and blood vessels, and the patients will not have obvious clinical symptoms. 2. Bone metastasis to the arm: if the malignant cells have metastasized to the arm through the bone, it may cause compression to the local blood vessels and nerves, and may induce clinical symptoms such as bone pain, difficulty in movement and numbness of upper limbs. In addition, symptoms such as pathologic fracture may also occur. In addition, metastasis to the arm, not only bone metastasis, but also soft tissue metastasis is possible. It is recommended that patients go to the hospital as soon as possible, and cooperate with doctors to receive chemotherapy, radiotherapy and other comprehensive treatment to inhibit bone metastasis as much as possible, so as not to jeopardize life and health.