The term "colon cancer" is sometimes used synonymously with colorectal cancer because cancers of the colon and rectum share some common characteristics. The rectum and colon make up the large intestine. Colorectal cancer is the fourth most common cancer in the United States and the second leading cause of cancer-related death .
Most colon cancers are caused by growths within the lining of the colon called polyps. How likely a polyp will turn into cancer depends on factors such as the type of polyp ( adenomatous polyps are considered precancerous) or the presence of abnormal cells (called dysplasia).