This study will recruit volunteers who continue to have difficult side effects after previous radiotherapy to the pelvis despite receiving the best treatments available from a unique clinic at The Royal Marsden which has pioneered treatment for bowel problems after radiotherapy. Two out of every three volunteers who take part, will be randomly assigned to treatment with Pentoxifylline and Tocovid SupraBio, while one out of three will receive dummy pills. Neither the patients nor the staff assessing them will know which treatment they have been given. Volunteers take the active treatments or dummy tablets for a year and will be assessed regularly while on treatment and for a year afterwards. This study will show whether active treatment is more effective than dummy pills in improving the symptoms caused by radiation-induced fibrosis.