The most important characteristic of malignant tumors is their aggressive and metastatic nature. Although the tumor is completely removed by surgery when it is first detected, and adjuvant chemotherapy is given after surgery for consolidation treatment, some patients still have recurrence or metastasis. 1. Surgery and chemotherapy have been done, but why do they still recur and metastasize? This is because a small number of tumor cells have been latent in some tissues or organs of human body since the beginning and are in dormant state, while chemotherapy drugs are powerless against dormant tumor cells. If these latent tumor cells are more immunogenic and the patient’s immunity is also stronger, these remaining cells may be gradually cleared by the immune system and the tumor will not recur. However, many times, tumor cells are able to camouflage well, causing the body’s immune system to fail to recognize them. After some time, these dormant tumor cells reactivate and grow rapidly, which leads to tumor recurrence and metastasis. This problem is still one of the problems in the medical field. 2.How to know the tumor has recurred and metastasized? After postoperative adjuvant chemotherapy, close follow-up is needed to detect possible recurrence or metastasis in time. The attending physician will usually make a follow-up plan for the patient and conduct relevant examinations regularly. For example, for lung cancer, checkups are conducted every 4-6 months for the first 2 years and then annually; for colorectal cancer, checkups are conducted every 3-6 months for the first 2 years and then every 6 months for a total of 5 years. The examination items usually include physical examination, blood tumor markers, imaging examinations such as CT and ultrasound, and gastroscopy and colonoscopy for patients with gastrointestinal tract tumors. Physical examination, blood tumor markers and ultrasound can be done frequently, while CT, endoscopy and other examinations should be done at relatively longer intervals. PET-CT examination can understand the metastasis of the whole body, but it is not used as a routine examination, only when necessary, it is chosen according to the doctor’s suggestion. 3.What are the most common sites for tumor metastasis? Different tumors have different metastatic sites, but in general, the metastatic sites are mainly lymph nodes, lung, liver, bone and brain. Therefore, when patients feel unexplained back pain, they should rule out whether there are lumbar spine, adrenal gland or retroperitoneal lymph node metastasis; if they have uncomfortable pain in the right upper abdomen, they should check the liver; if they have dizziness, headache or even vomiting, they should pay attention to whether there are brain metastasis; if they have pain in the chest and back or dry cough, they should check the lung metastasis; if they feel nodes in the armpit, supraclavicular fossa, neck or groin, they should pay attention to rule out the possibility of lymph node metastasis. Metastasis is a possibility. However, many patients do not have any symptoms at the early stage of metastasis, so you should not wait until symptoms appear before going for examination, but should be examined regularly according to the doctor’s advice. 4.What should I do after the diagnosis of recurrence or metastasis? Once the diagnosis of recurrence and metastasis is confirmed, the patient and family members will undoubtedly suffer a second blow, but the first thing to do at this time is to try to find ways to stabilize the emotion, especially to comfort the patient (requiring joint action of family members and doctors), and to inform the patient that there are still good treatments available after recurrence, and sometimes even long-term survival, and that maintaining confidence is the fundamental to get good treatment results. Some matters that family members and patients need to pay attention to after tumor metastasis can also be referred to the article “What to do after first diagnosis of tumor (cancer)?” on Dr. Jiang Bin’s personal homepage. . Generally speaking, most recurrent or metastatic tumors do not require further surgical treatment. In a few cases, surgical resection can be considered, such as isolated resectable metastases in the brain or adrenal gland after lung cancer surgery (which can also be treated with stereotactic radiation therapy), or resectable local recurrence in the lung, which can be surgically removed and then treated with other treatments. Most recurrent or metastatic tumors usually require a non-surgical combination of treatments such as chemotherapy, radiotherapy, interventional therapy, targeted therapy, supportive therapy, etc. Unlike the radical treatment for early-stage primary tumors, the ultimate goal of treatment for advanced recurrent or metastatic tumors is to enable patients to “survive with tumors for a long time”. However, it should be noted that the efficacy of any treatment needs to be evaluated periodically, and one cannot keep using one regimen with eyes closed. If the chemotherapy regimen used is not effective, or if it starts to be effective and becomes resistant after a few times, the efficacy evaluation will tell you that once it is found to be ineffective, you need to stop it immediately and consider changing the treatment strategy and regimen. If the relevant regimen is already ineffective, continuing to use it will undoubtedly make the patient delay and suffer. When the treatment reaches a certain stage and the tumor is stabilized, it can be changed to maintenance therapy to achieve long-term survival with tumor. And the treatment strategy can be adjusted at any time according to the results of regular checkups. The treatment of patients who are older or have a slightly poor physical condition needs to be reduced in intensity. If the patient is in poor physical condition and cannot tolerate the related anti-tumor treatment, the best supportive treatment can be given, which may not necessarily prolong the survival period but can maximize the survival quality of the patient. 50-80% of patients with tumor metastasis may be accompanied by cancer pain, which is one of the most common symptoms in advanced tumor and one of the most painful symptoms for patients, and many family members and patients often refuse or resist Many family members and patients often refuse or resist analgesic treatment, and there are great misunderstandings about cancer pain treatment. Scientific understanding and standardized treatment of cancer pain is a key point of advanced tumor treatment.