How would you treat an isolated recurrence in the pelvic muscle after prior definitive chemoradiation with brachytherapy boost for vaginal adenocarcinoma?

Assume surgery is not an option. Would you encompass the entire involved muscle and treat with fractionated RT, or would you use SBRT to treat the discrete PET-avid disease focus? Previous pelvic RT delivered around 35 Gy to the recurrent area one year prior.