Cancer cells often travel to other parts of the body where they can grow and form new tumours that crowd out normal tissue. This happens when the cancer cells get into the body’s bloodstream or lymph vessels. The process of cancer spreading is called metastasis.
No matter where a cancer may spread, it’s always named based on the place where it started. For instance, colon cancer that has spread to the liver is called metastatic colon cancer, not liver cancer. In this case, cancer cells taken from the liver would be the same as those in the colon. They would be treated in the same way, too.