Lymphatic tract metastasis Lymphatic tract metastasis is one of the most common metastatic pathways of malignant tumors. It is common in all kinds of cancers. Cancer cells invading into lymphatic vessels firstly arrive at local lymph nodes with lymph, and then can be transferred to neighboring or distant lymph nodes with further development. For example, breast cancer can firstly metastasize to ipsilateral axillary lymph nodes, and then metastasize to subclavian and supraclavian lymph nodes, or even contralateral axillary lymph nodes. Bloodway metastasis Bloodway metastasis refers to malignant tumor cells spreading to distant organs through blood circulation. It is common in various sarcomas, endocrine carcinomas and undifferentiated carcinomas. Tumor cells directly invading into blood vessels or re-entering into blood vessels through lymphatic vessels arrive at other parts of the body with blood flow. The most common sites of metastasis are lung, brain, liver and bone. Gastrointestinal tract cancer often metastasizes to liver and lung, breast cancer, kidney cancer, osteosarcoma often metastasizes to lung, lung cancer easily metastasizes to brain, and prostate cancer easily metastasizes to bone. Plantation metastasis Plantation metastasis, also known as transplantation metastasis, refers to the plantation growth of tumor cells detached from the surface of tumor in thoracic cavity, abdominal cavity and cerebral spinal cord cavity, etc. Due to gravity, it tends to be planted in the lower part of these cavities, such as rib-diaphragm angle, rectal bladder fossa, skull base, etc. This is the only way to prevent the metastasis from spreading to the liver and lung. This is another common metastatic route for malignant tumors other than the lymphatic and blood channels.