The body is made up of many types of cells. Normally, cells grow and divide to produce more cells only when the body needs them. This orderly process helps keep the body healthy. Sometimes cells keep dividing when new cells are not needed. These extra cells may form a mass of tissue , called a growth or tumor .
Cancer can begin in any organ or tissue of the body.
The original tumor is called the primary cancer or primary tumor and is usually named for the part of the body in which it begins. Metastasis means the spread of cancer. Cancer cells can break away from a primary tumor and travel through the bloodstream or lymphatic system to other parts of the body. This is called nodal involvement, positive nodes, or regional disease. Cancer cells can also spread to other parts of the body, distant from the primary tumor.