Bowel surgery. Surgeons performing bowel surgery on a patient with colon cancer. The patient's abdomen has been cut open and the surgeons are removing cancerous tissue from the lining of the colon (local resection). This procedure is carried out only if the cancer is detected early. The colon is part of the large bowel, and is the area where water is absorbed from digested food and faeces are formed. Cancerous growths can cause constipation, diarrhoea or malabsorption and sometimes part of the colon will need to be permanently removed.