Colorectal cancer typically begins in the colon or the rectum with asymptomatic, small, benign clumps of cells, which can develop into cancer with time. Colorectal cancer is the third most common cancer diagnosed, and the third leading cause of cancer-related deaths in the United States. The American Cancer Society estimates that there will be 102,900 new cases of colon cancer, 39,670 new cases of rectal cancer, and 51,370 deaths attributed to colorectal cancer in 2010. Colorectal cancer incidence rates have been decreasing for most of the past two decades, largely attributed to better screening and removal of colorectal polyps before they develop into cancer. Advanced and/or recurrent colorectal cancer is associated with a poor prognosis.