Cancer is a group of more than 100 different diseases characterized by the uncontrolled, abnormal growth of cells that form a tumor. Some cancers, such as blood cancers, do not form tumors. Benign (non-cancerous) tumors may grow, but they do not spread to other parts of the body and are usually not life threatening. Malignant (cancerous) tumors grow and invade other tissues in the body. Cells from malignant tumors can also break away and travel to other parts of the body, where they can continue to grow, a process called metastasis. 2. Cancer is not one disease but dozens of diseases.

Some cancers can be found early by physical examinations by a health professional (such as examination of the skin), specific examinations (such as a colonoscopy to look inside the rectum and the colon) and X-ray or laboratory tests (such as mammography and the Pap test). A combination of these approaches is the most effective strategy for early detection, and early detection increases the likelihood of effective treatment.3. Early detection is key.

People of all ages, including children, can develop cancer, but most cancers occur in people over the age of 65. Certain risk factors that increase the chance of developing cancer are old age, tobacco use, overexposure to sun, ionizing radiation, certain chemicals, some viruses and bacteria, certain hormones, family history of some types of cancer, alcohol abuse, being physically inactive and obesity. By avoiding known risk factors, cancer risk may be reduced. 4. Cancer is primarily a disease of older people.