Understanding the Cancer Process
Understanding the Cancer Process
Cancer is a group of many related diseases that begin in cells, the body's basic unit of life. Normally, cells grow and divide to produce more cells only when the body needs them. Sometimes, however, cells keep dividing when new cells are not needed. These extra cells form a mass of tissue called a growth or tumor. Tumors can be benign or malignant.
Benign tumors are not cancer. They can usually be removed, and in most cases they do not spread to other parts of the body, and are not a threat to life.
Malignant tumors are cancer. Cells in these tumors are abnormal. They divide without control or order, and can invade and damage nearby tissues and organs. Cancer cells can break away from a malignant tumor and enter the bloodstream or lymphatic system. That is how cancer spreads (metastasizes) from the original (primary) cancer site to form new tumors in other organs.