It means to spread, as in a diseased tumor as it spreads to other parts of the body. So if someone had cancer of the stomach, it could spread (metastisize) to the lungs and start growing there as well as the stomach.
Do a search for the effects of Lung Cancer. The original source (Thyroid) is immaterial.
Metastasis is a common word used when referring to cancer. If something is said to have metastisized it means that it is on the move in the body, moving from location to location. This causes the tumor, clot, or cancer to be able to spread throughout the body, thus effecting more of the body and killing is sooner.
It had spread too much. Trying to remove as many as possible would have made her life even harder and she could've gotten infections on top of still having cancer. They could not remove them all..
Cancer that originates in or metastisized to the brain affects 190,000 new victims every year according to the National Brain Tumor Society (USA). There is no set expiration date on someone with brain cancer from any source. It just depends on too many factors, which include: exactly where the cancer is, what stage the cancer is in, what type of cancer it is, and that's just the beginning. With the multitude of treatment options today, there is every reason to expect that most people who experience brain cancer can live a full life.