Colon cancer is a disease that affects the large intestine, an organ that absorbs the nutrients from the food, and stores and eliminates the fecal material. The large intestine has two parts, the colon and the rectum. Colon cancer occurs when tumors appear inside the colon and rectum. These tumors can be malignant, in which case they do not present any danger and they can be removed by a simple surgery, and beningn. Beningn tumors are cancerous tumors that can spread and cause life-threatening complications.