Late complications of pelvic radiotherapy occur in 5-20% of patients, particularly chronic radiation proctitis (CRP). Rectal bleeding is the most common symptom. Other symptoms include difficulty in defaecation or tenesmus because of loss of distensibility of the rectum or rectal structuring. Treatment options of CRP include oral therapy (5-aminosalicylates, metronidazole), rectal instillation therapy (hydrocortisone, sucralfate, 5-aminosalicylates, formalin), thermal therapy (argon plasma coagulation, heater probe or laser) and hyperbaric oxygen. It is difficult to recommend evidence-based therapy. There are no adequately powered studies of the treatment of CRP and most data are uncontrolled, non-blinded observation studies from single sites. There are no standard evaluation tools (including endoscopic grading, symptom scores and quality-of-life scores), adequate description of preceding radiotherapy dose or adequate follow-up in most studies. Many studies have poor documentation of complications and few are carried out prospectively. A pragmatic approach is to use sucralfate enemas and oral metronidazole. Thermal methods seem to be effective and safe. Simple heater probe treatment or argon plasma coagulation are the preferred methods due to their better safety profile. Intra-rectal formalin seems to be effective, but possibly has a higher rate of complications. For resistant disease, hyperbaric oxygen may be an option.

Leiper, Morris, , , , , , , (2007). Treatment of radiation proctitis. Clinical oncology (Royal College of Radiologists (Great Britain)), 2007 Nov;19(9):724-9. https://www.ncbi.nlm.nih.gov/pubmed/17728120