Chronic Radiation Induced Bowel Toxicity Study

This is a prospective, translational study which aims to investigate the radiation induced immunological changes in the bowel mucosa, blood and urine, and the role of the microbiota in acute and late bowel toxicity. The investigators aim to recruit 50 patients newly diagnosed with (histologically confirmed) localised, intermediate to high-risk prostate cancer (T2b -T4a N0 M0), who are due to undergo standard of care radical radiotherapy (Intensity modulated radiotherapy (IMRT)) (60Gy in 20# with curative intent) 4-week regimen. Eligible patients who have consented to the study will provide the following samples at baseline (prior to the start of radiotherapy), weekly during radiotherapy for 4 weeks, 6-8 weeks and 12 from the start of radiotherapy, and at 6-month and 12-month follow-up appointments: 1. stool sample 2. blood sample (40mls) delegated nurse or research nurse. 3. mid-stream urine sample 4. optional rectal swab 5. quality of life health questionnaire 4-day diet diaries will be completed by the patients in the 4 days prior to providing their baseline stool samples and at follow-up appointments (6-8 weeks, 6 months, 12 months).