Multiple metastases refer to metastasis in multiple organs other than the primary tumor lesion, such as rectal cancer causing lung metastasis, liver metastasis, brain metastasis, bone metastasis and so on. Malignant tumors originating in other parts of the body and metastasizing to the lungs are quite common, and most of them are hematogenous metastases. Common primary malignant tumors include gastrointestinal tract, genitourinary system and liver, thyroid, breast, bone, soft tissue, skin cancer and sarcoma. When the patient has multiple metastases, it usually suggests that the condition is aggravated and the patient’s vital signs should be closely monitored.