When do you use a brachytherapy vaginal cuff boost in postoperative cervical cancer treatment?

I limit use to close or positive margins, or if the patient has had an incidental simple hysterectomy done instead of a radical hysterectomy.

I agree with @Dr. First Last regarding vaginal cuff brachytherapy boost for close or positive vaginal radial margin. We would do so whether it was a simple or a radical hysterectomy given the presence of positive vaginal margin. We would not do the boost just for positive LVSI.

Patients receive 4500 cGy to the pelvis (180 cGy/fraction) and vaginal cylinder HDR brachytherapy 500 cGy X3. I would add that if the parametrial margin is close or positive, we would instead use external beam boost to better encompass the lateral parametrial region as vaginal brachytherapy boost does not provide this lateral dose coverage.

In planning the radiation treatment volume, dose, and technique in the post-hysterectomy setting, multiple factors that include simple versus radical hysterectomy, parametrial/vaginal margin status, Sedlis risk factors (depth of stromal invasion, LSVI, lesion size) have to be addressed for the individual patient.