WHAT IS CANCER?
The word cancer refers to a group of almost 200 different diseases that all start when some of your body’s cells become abnormal, growing and multiplying very quickly. Normally, your 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 may form a mass of tissue called a growth or tumor. A tumor may be benign (noncancerous) or malignant (cancerous).
Unlike normal cells, cancerous cells multiply without any control and don’t self-destruct or die when they become worn out or damaged. Cancerous cells crowd out healthy cells and prevent them from doing their jobs. They can also invade surrounding tissue or spread to distant areas of the body where new tumors form, a process called metastasis.
What Causes Cancer?
Cancer has no single cause. Usually we do not know the exact cause of a cancer. The body contains trillions of cells and each cell contains DNA, which makes up thousands of genes that determine what the cell is supposed to do. Scientists have found that when certain genes are abnormal or become damaged, the cell may become cancerous. Although scientists have identified some factors such as chemicals in cigarette smoke and radiation from the sun that can increase the risk of cancer, there is currently no way to know exactly what factors were involved in starting your cancer. We do know that cancer is not contagious (you can’t catch it from someone else), and there is currently no evidence that high levels of stress or anxiety cause cancer