In a surgically staged Stage II Grade 1 endometrial adenocarcinoma, with no other high risk factors, would you treat with brachytherapy alone or add on the pelvic RT?

Yes, the current stage II was excluded from PORTEC 1 and 2 and were part of GOG 99 and GOG 249. With stromal invasion there is risk of nodal, vaginal, and parametrial (if only simple hysterectomy was done) recurrence, and for that reason we offer pelvic EBRT. That being said, if stromal invasion is 1 to 2 mm (we ask the pathologist to quantify), then in staged patients we offer brachy alone.

In our study of Stage II patients treated with VBT alone, pelvic failure was low, at only 4% at 5 years of follow up. When looking at patients with the most favorable features—microscopic Stage II, G1-2, no LVI, FIGO IA, with a nodal assessment—there were no pelvic failures among 31 patients. I agree with @Dr. First Last's assessment of depth of cervical stromal invasion as a potential high risk feature, though this data was not available for most patients in our study. So I use VBT in patients ...

I agree with all above responses. One must evaluate all risk features, but in low grade (1/2) no LVSI, depth of invasion of cervical stroma are important factors to consider, and in most of these patients, vault only would be sufficient.

We recently published our data, and did find that patients with G3 or serous histologies treated with vaginal vault had higher risk of recurrence, but most of these recurrences were distant.

I agree with the above opinions, if no other risk factors were identified and all surgical margins are Path negative.