6x R-CHOP is probably fine and you dont really need XRT after it, if you have a complete remission.
If you are going to give less chemo than 6x R-CHOP, you should irradiate with 30 Gy, that's certainly so.
Medgator is strictly speaking right. In all rituximab registration trials, extranodal disease was irradiated. So, this lady would have gotten XRT in the trials.
On the other hand we have quite good retrospective data, showing that you can ommit RT in Stage I patients with extranodal disease being treated with intensive (6 cycles) chemotherapy + rituximab, if they show complete remission.