In what setting do you omit adjuvant radiation therapy in a T3N0 rectal cancer?

The NCCN guidelines categorically recommend adjuvant XRT for a cT1-2N0 rectal adenocarcinoma upstaged to a pT3N0, yet there are multiple institutional series with low recurrence rates with surgery alone in T3N0 patients in whom adjuvant chemoradiation is omitted. This questions presumes high-volume colorectal surgeons performing good TMEs with negative margins.