I just looked at the treatment guidelines, and they say for stage 1A and grade 1 or 2 that "observation preferred" or "consider vaginal brachytherapy if lymphovascular space invasion (LVSI) and/or age >60".

Treatment guidelines are intended to standardized treatment across the country and provide the best outcomes for the most patients, given current knowledge. They keep the possibility of over-treatment in mind, both to prevent patients from having side effects from unnecessary treatments and to manage the unavoidable conflict of interest in our current medical system that doctors and hospitals make more money with more treatment. How many people should receive unnecessary treatment to prevent one recurrence?

I definitely understand your desire to do everything possible, but in my view observation could be your best course of action in that situation. Vaginal brachytherapy isn't horrible, but it does cause some issues. Also, I have read a lot of this literature, and my impression is that low grade recurrences in the vaginal cuff are frequently cured on the first recurrence and do not keep coming back. But that's a good question for your doctor.

Post-hysterectomy radiation therapy for endometrial cancer has been at least common (and possibly universal) since the 30's or 40's. My great-aunt had radiation therapy after her hysterectomy in 1942 or 43, probably at the U of Minn. She was a farm girl (she had cancer when she was 27) from western WI, so not privileged. This was external radiation; VB was developed much more recently. My impression was that it is only more recently that they stopped doing external pelvic/abdominal radiation on everybody, either because they realized which patients needed no treatment or because there were other options like VB and chemo.