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metastasis

(meh-TAS-tuh-sis)
The spread of cancer cells from the place where they first formed to another part of the body. In metastasis, cancer cells break away from the original (primary) tumor, travel through the blood or lymph system, and form a new tumor in other organs or tissues of the body. The new, metastatic tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the lung, the cancer cells in the lung are breast cancer cells, not lung cancer cells.
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Metastasis; drawing shows primary cancer that has spread from the colon to other parts of the body (the liver and the lung). An inset shows cancer cells spreading from the primary cancer, through the blood and lymph system, to another part of the body where a metastatic tumor has formed.Enlarge this image in new window
Metastasis. In metastasis, cancer cells break away from where they first formed (primary cancer), travel through the blood or lymph system, and form new tumors (metastatic tumors) in other parts of the body. The metastatic tumor is the same type of cancer as the primary tumor.
Many cancer deaths are caused when cancer moves from the original tumor and spreads to other tissues and organs. This is called metastatic cancer. This animation shows how cancer cells travel from the place in the body where they first formed to other parts of the body.
Search NCI's Dictionary of Cancer Terms