Carcinomatous toxin is the pathogenic factor of cancer.The metastasis of carcinomatous toxin is resulted in cancer metastasis.In physiological conditions

there are meridians

qi thoroughfare

four-sea passages

sanjiao

membrane-source and interstices in human body to transport various substances.While in pathological conditions

carcinomatous toxin can spread through these passages.Based on modern medicine

cancer can spread from where it started to other parts of the body through blood vessels

lymphatic vessels and other means

and prognosis is closely related to the way of cancer metastasis.Therefore

it is important to study the metastasis of carcinomatous toxin according to TCM theory on passages in prevention and treatment of tumor metastasis.