Treatment will depend on the size of the tumor, it's position and whether it has spread. Surgery is the most common treatment- the part of your large bowel with the cancer is removed and the two open ends joined together. Lymph nodes (glands, part of your immune system) near your bowel are often removed because the cancer usually spreads there first. Sometimes the second bowel ends can't be rejoined. So, the opening nearest the beginning of your bowel is brought out on to the skin surface of your abdomen to form a colostomy. (An ileostomy is an opening of your small bowel onto the surface). The opening of the bowel is called a stoma. A bag is worn over the stoma to collect your bowel movements outside your body. Most people don't need a colostomy but if you do, it's usually temporary and reversible.
Attribution: BUPA