In clinical practice, it is common to see some patients with cancer pain, who start to have severe pain, but at the late stage, the pain suddenly disappears, this situation represents whether the patient’s cancer is improving or deteriorating. Clinically, there are more reasons for this situation, such as: 1. At the late stage, the nerve compression invaded by cancer is too heavy, the nerve sensation is not sensitive, and the pain will be relieved; 2. There are also tumors with envelope, after cancer pain invades the envelope or invades the organ envelope, if the envelope ruptures or the pressure on the envelope is reduced, it can also make the pain suddenly relieved. If this happens, it is better to go to the hospital to check whether there is any organ rupture or other conditions to facilitate timely diagnosis and treatment; 3. clinically, patients with sudden pain relief may be in poor physical condition, their mental state is also poor, their consciousness is relatively unclear, and their pain is relatively relieved; 4. clinically, many painkillers may be used to relieve pain within a short period of time, which are painkillers that continue to play the role of pain relief. in playing a pain-relieving role for a short time may also lead to temporary pain relief in patients.