Tumor is the number one disease that threatens human health. It is not terrible to have tumor, but the tricky part is tumor metastasis. Tumor metastasis refers to the process that malignant tumor cells are separated from their primary sites and reach different tissues and organs in the body through various ways to continue to proliferate and grow into tumors of the same nature. For example, Master Wang’s lung cancer is considered to have metastasized to the lumbar spine through blood transmission, producing the symptoms of bone metastasis of lung cancer. The original tumor is called primary tumor and the newly formed tumor is metastasis. The metastasis of tumor is a complex biological process involving multiple genes, cytokines and other participation. There are many factors leading to tumor metastasis, such as the higher the malignancy of tumor tissue, the earlier the metastasis occurs; the poor physical condition and low immune function of patients will also increase the chance of tumor metastasis. If tumor metastasis occurs, it means the tumor lesion has developed to advanced stage, which is also one of the important reasons for tumor cure failure. Among the newly diagnosed tumor patients in China, 2/3 of them already have metastasis when they first visit the doctor. Why does lung cancer travel to the lumbar spine? The occurrence of tumor metastasis is not random, preferably in a specific organ, and there are also differences in the chance of metastasis and the time of metastasis occurrence. The mechanism of tumor metastasis is not well understood and is related to the characteristics of the tumor cells themselves and the body’s defense function. One well-known theory is the “seed-soil” theory, which suggests that tumor cells are like seeds, which usually metastasize selectively to the microenvironmental soil that is more suitable for their rooting, nutrition, and growth and development. For example, lung cancer tends to metastasize to liver, bone and brain, breast cancer tends to metastasize to lung, bone and brain, colon cancer tends to metastasize to lung and liver, prostate cancer tends to metastasize to bone, while brain tumors rarely metastasize to other organs, while brain is the ideal “soil” for other tumors to metastasize. Each gram of tumor tissue can release 3-4 million cancer cells into the blood every day. Once the conditions are ripe, the scattered cancer cells will be planted in body tissues and organs like seeds and grow up rapidly, destroying the function of organs and eventually leading to the patient’s death. Just because tumors can metastasize, some patients come to the clinic because of the discomfort in the metastatic parts of the tumor, and then discover the tumor. For example, Mr. Wang came to the hospital because of the early symptoms of bone metastasis and back pain. The lymphatic vessels are part of the lymphatic system, and their structure is similar to blood vessels, which are responsible for transporting lymphatic fluid containing protein, fat and lymphocytes in the form of milk. Tumor cells can metastasize to other parts along lymphatic vessels, especially tumors in stomach, pancreas, lung, breast, colon, nasopharynx and other parts are common. Lymphoma takes lymphatic metastasis as the main metastatic mode. The clinical manifestations are mostly progressive enlargement of lymph nodes. Bloodstream metastasis Tumor cells enter blood vessels and metastasize to other parts along the direction of blood flow. Most tumors can metastasize through this route. C. Implantation metastasis means cancer cells are shed from the primary site and spread on the surface of other organs. For example, peritoneal metastasis, ovarian metastasis (also called krukenberg tumor) and pelvic metastasis can occur in the late stage of gastric cancer. Can tumor metastasis be prevented? Although there are no targeted drugs to prevent tumor metastasis, early detection and early treatment can be achieved through the following measures. Regular medical checkups Regular checkups can not only detect metastatic tumors at an early stage, but also help to detect early tumors. For example, for lung cancer, the National Comprehensive Cancer Network (NCCN) expert group recommends the use of low-dose spiral computed tomography (LDCT) for lung cancer screening in high-risk groups; it is not recommended to perform lung cancer screening for individuals with moderate or low risk. Chest X-ray is not recommended for lung cancer screening. Do not ignore the uncomfortable symptoms and do not take it for granted to treat yourself. You should go to regular medical institutions for treatment. Regular follow-up For patients after surgery, follow up and review regularly according to medical advice. V. Choose a healthy lifestyle Encourage all cancer survivors to adhere to a healthy lifestyle, pay attention to weight management, physical exercise and develop healthy eating habits. Having cancer does not mean that you need to be “kept” and immobile. Healthy lifestyle habits are associated with improved overall health and quality of life. For some cancers, a healthy lifestyle is associated with a reduced risk of tumor recurrence and mortality. What if metastasis occurs? For tumor patients, once the tumor has metastasized, it is more important to actively cooperate with doctors and individualized treatment is a wise choice. The treatment methods include chemotherapy, radiotherapy, surgery, palliative care, etc. With the application of targeted drugs in clinical practice, the development of translational therapy and the advancement of treatment technology, many patients with metastasis can still survive with tumor for a long time. For patients who are not suitable for chemotherapy, radiotherapy or surgery, palliative care can also reduce pain and improve quality of life through methods such as palliative care. Palliative care is a treatment method for patients with mid to late stage tumors, which can improve the quality of life and prolong the survival time of patients with advanced stages. Pain and tumor-related complications are managed, and psychological, social and spiritual issues are taken into account. Palliative care is also applicable to patients with early stage tumors. It is worth noting not to rush to doctors, not to believe in prescriptions and not to treat in informal medical institutions in order to get standardized and effective treatment.