At the beginning of the attack of bone cancer, that is, malignant tumor of bone, patients may have local pain, weakness, muscle spasm and other precursors. Some patients may not have obvious precursors, but the precursors are as follows: 1. Local pain: in the area where the lesion appears, due to the local destruction of bone quality and the compression of the lesion on the periosteum or peripheral nerves, obvious local pain will be induced. The pain will be significantly intensified when the patient tries to press with his hands. 2. Weakness: when these patients are engaged in some intense physical activities or heavy physical labor, they will have obvious symptoms of fatigue, and their physical ability will be reduced. 3. Muscle spasms: due to the destruction of bone and the imbalance of calcium metabolism in the body, this kind of patients are very prone to muscle spasms at night or when they are cold. It should be noted that the above precursors are often atypical. Therefore, when the above symptoms appear, the association with bone tumors may not be particularly significant. Patients are advised not to be overly alarmed when the above symptoms occur, but to consult an orthopedic surgeon in time.