Would you offer additional radiation in a young patient with T4N1 rectal cancer, s/p TNT and pelvic exenteration with a positive deep margin without gross disease seen on post-operative imaging?

This is a very difficult decision. Although somewhat arbitrary, it is considered desirable to have at least a 6-month interval, preferably a year, before considering re-irradiation. For a patient who had surgery following TNT, the interval since the first course of radiation is presumably only a few...