There are two kinds of conditions that cause arm numbness: one is vascular lesion, such as arterial occlusion or venous embolism, which may lead to numbness and soreness in the arm; the other condition is that the nerve root is compressed, such as cervical spine lesion compressing the local nerve root, which may lead to soreness and numbness in one arm, accompanied by weakness. Patients need to go to the hospital to clarify the specific cause of the disease. Most of the cancers are solid tumors, but if the patient has lymphoma and presses on the local nerve, the above symptoms may occur. Or stomach cancer may metastasize to the left clavicular lymph node and compress the local nerve to induce the above symptoms. However, the incidence of this type of cancer is relatively low. In addition, patients usually have other non-specific symptoms, such as wasting, poor blood circulation and increased blood sedimentation.