What is the appropriate treatment for a low lying rectal cancer in the setting of prior definitive prostate IMRT?

As is true for most complicated clinical situations, there is not any absolute answer to this question.

First, it does allow me to remind everyone that prostate radiation therapy increases the incidence of subsequent rectal cancer- probably about 2 fold. This shouldn't surprise anyone, but it is something to keep in mind. I think that prostate cancer patients should have their colon followed as one would an intermediate risk patient (colonoscopies every 5 years, not ten), although one could argue for sigmoidoscopies as the increased incidence is in the rectum, not in most of the rest of the colon.

Having said that, there is no clear answer as to how to manage these patients. We should keep in mind that most studies have not shown a survival a...