I know we always say knowledge is power,sometimes it can be counterproductive.Knowing too much can cause preemptive anxiety.Part of the success of this disease is having confidence in your doctors.If your problem is that you can't or won't accept what you are being told,then your first option is to get a second or even third opinion.I would imagine that when the lymph node was removed the surgeon had a good view of the surrounding tissues and would have been able to see if there were clear margins or not,and as he has said no RT i guess the answer would have to be the margins were clear.If they weren't then she has other options such as chemo or further RT and further surgery would also be a probable otion.
Bottom line is all this will become clear when the pathology and scans are all looked at together and the doctors have a clearer picture There are two schools of thought here,throw everything but the kitchen sink at it first time,or hold something in reserve for future complications.