Colon cancer is a type of cancer that affects the large intestine (colon). It is the third most common type of cancer in both men and women. Symptoms of colon cancer can include changes in bowel habits, such as diarrhea or constipation, blood in the stool, abdominal pain, and unexplained weight loss. If left untreated, colon cancer can spread to other parts of the body. Treatment for colon cancer typically involves surgery to remove the cancerous tissue, followed by chemotherapy and/or radiation therapy. In some cases, a combination of treatments may be used. The prognosis for colon cancer depends on the stage of the cancer at the time of diagnosis. Early detection and treatment can improve the chances of a successful outcome.