C olorectal cancer is a major public health issue, particularly in industrialized nations. In the United States, an estimated 138,900 people are newly diagnosed with colorectal cancer each year and about 57,100 people die of the disease. Among women, colorectal cancer is the second most common cancer, after breast cancer. Among men, colorectal cancer is the third most common cancer, after prostate and lung cancers. The incidence among blacks in the United States has increased since the early 1970s, but the reason for this is unclear.
Cancer is an abnormal, uncontrolled growth of cells .
In cancer, cells proliferate out of control and the abnormal growth of cancerous cells form tumors, which can cause other body tissues to be destroyed. A benign tumor is not cancerous. The cells in a benign tumor look like normal body cells. Although benign rumors can grow large enough to interfere with normal body functions, they do nor spread to other parts of the body. Benign tumors that are removed rarely return.