Both external and internal factors cause cancer. Factors such as chemicals, radiation, viruses, hormones and inherited mutations may act together to start or further cancer. Ten or more years may pass between exposure and detectable cancer. Anyone, from children to senior citizens. In the 1980's, there were over 4.5 million cancer deaths, almost 9 million new cancer cases, and about 12 million people under medical care for cancer.
People can avoid some external factors.
For example, skin cancer can be avoided by using sun protection. Eating a high-fiber diet may help prevent other forms of cancer. Not smoking or drinking heavily can also help you avoid cancer. Regular health care can also help catch cancers at an early stage. More than 10 million Americans are estimated to have a history of cancer.