How would you manage a patient who received pelvic radiation 15 years ago and now has a 5 cm colon adenocarcinoma and squamous cell carcinoma of the anorectum?  

I think the objective in a retreatment case like this is to maximize the chances of curing cancer with as little RT as possible. I would consider disease free survival with a functioning colostomy a better outcome than survival with an intact rectum but chronic difficult-to-manage complications...