Once someone has been treated for radiation colitis is it necessary to be treated again ? symptoms from it have reappeared after 5 years.

Discuss: with your radiation oncologist. Multiple individual factors play a role in such decisions

Yes: Radiation enteritis can presents with long and short term complications up to 30 years following initial exposure. Cellular changes, includes submucosal fibrosis, vasculitis (arteritis, veno-occlusive diseases), thrombosis, tissue necrosis resulting can occur as long term complications of acute radiation injury.