metastasize
Meaning of metastasize: A tumor in the liver made of colon cells is still colon cancer, which is why origin governs treatment rather than address.
Definition of metastasize
To metastasize is for cancer cells to leave the tumor where they started and establish new tumors somewhere else in the body. The cells in the new growth resemble the original tumor rather than the organ they land in, so a breast cancer growing in bone is still made of breast cancer cells. The word applies to cancer and to nothing else.
How do cancer cells travel?
Spreading is a sequence, and failure at any step ends it. Cells first loosen the attachments holding them to their neighbors, then break through the thin sheet of tissue that normally confines them. They enter a small blood vessel or a channel of the lymphatic system, and most die there, destroyed by immune cells or by the mechanical stress of circulating. A few survive, lodge where a vessel narrows, cross its wall into the surrounding tissue, and then face the hardest step of all: growing in an unfamiliar place, which means persuading that tissue to build new blood vessels. Many cells that arrive never manage it and lie dormant instead, sometimes for a very long time before growing. Cancer can also spread without using vessels at all, by shedding cells directly across the inside of the abdomen or the chest.
Why does each cancer favor particular sites?
| Cancer of origin | Common sites of spread |
|---|---|
| Breast | Bone, liver, lung, brain |
| Colon | Liver first, then lung |
| Prostate | Bone, particularly the spine and pelvis |
| Lung | Brain, bone, liver, adrenal glands |
Part of the explanation is plumbing, since blood leaving the bowel passes through the liver before anywhere else, so that is where its cells arrive. The rest is compatibility: a cell only takes hold where the surrounding tissue offers signals it can use.
How is spread different from recurrence?
Three situations get confused with one another. A secondary cancer is the same disease growing at a distance, built from cells of the original tumor. A local recurrence is the same disease returning at or near the site that was treated. A second primary cancer is a genuinely new and unrelated cancer arising later, and under the microscope it looks like the organ it started in rather than the first tumor. The distinction is not academic, because treatment follows the cell of origin rather than the location. It also explains the naming convention: a deposit in the liver from a colon cancer is called metastatic colon cancer, never liver cancer.
Used in a sentence
The oncologist explained that the cancer had begun to metastasize to nearby lymph nodes.
Good to know
When a cancer metastasizes, this describes the spread of the disease itself, a distinct process from cancer recurrence, in which cancer returns at or near the original site sometime after treatment.
Word origin
Where “metastasize” comes from
Formed from Greek meta-, meaning beyond or change, and stasis, meaning a standing or placement.