What is Colorectal Cancer?
Colorectal cancer (CRC) is characterized by the uncontrolled growth of abnormal cells in the colon or rectum. The colon and rectum are the final part of the gastronintestinal system and are sometimes called the large intestine where food is processed for energy and rids the body of solid waste (fecal matter or stool). The large intestine is sometimes called the large bowel, which is why CRC is sometimes referred to as bowel cancer.
CRC usually begins as a polyp, a noncancerous growth on the inner lining of the colon or rectum, and grows slowly over a period years. Most polyps do not develop into cancer. Once cancer forms in the inner lining of the colon or rectum, it can grow into the wall. Once this happens, the cancer can invade the blood system and lymph nodes and then travel to other structures, including the liver, lungs and abdomen. This process of spreading from the original site is called metastasis.
1For more information, visit the American Cancer Society web site on colorectal cancer.