RATIONALE FOR PERFORMING THE STUDY Colorectal cancer This is the third most common cause of cancer and cancer death in both men and women (40,000 cases and just under 16 000 deaths per year in the UK). Worldwide, there are approximately 1 million cases and 500 000 deaths per annum. Primary treatment is usually surgical with, in appropriate cases, adjuvant or neo−adjuvant therapy currently including radiotherapy, cytotoxic chemotherapy or a combination. Unfortunately, the overall survival of locally advanced disease is at best 50%. Many patients who have residual, refractory or recurrent rectal cancer experience serious morbidity from local tumour invading and destroying adjacent tissues including bone, nerves (sacrum), bladder and the skin. These interfere severely with normal daily activities, especially bowel function and cause great distress in terms of pain, with many patients requiring permanent palliative colostomies.