When would you add a vaginal cuff brachy boost to external beam radiation for uterine carcinosarcoma?

Would you offer EBRT alone or EBRT with vaginal cuff brachytherapy after surgery and chemotherapy for stage III (T3N0) carcinosarcoma of the uterus? Given propensity for advanced stage carcinosarcoma to recur distantly, what is the utility of adding vaginal cuff brachytherapy to EBRT, if any? Which pathologic factors would influence this decision? - +/- lymphadenectomy, % myometrial invasion, depth of invasion, uterine serosal involvement, lower uterine segment involvement, cervical stromal invasion, LVI, and/or lymph node involvement.