What is your preferred management for persistent viable cervical tumor 6 months after high-quality chemoradiation with KEYNOTE A-18 regimen for locally advanced cervical cancer?  

6 months after high-quality EBRT+HDR with cisplatin + pembrolizumab (A18 protocol), PET demonstrates resolution of nodal disease and substantial improvement in cervical avidity, but residual FDG-avid central pelvic tumor approximately 2cm in size. Office exam demonstrates no obvious disease. Assuming upcoming EUA with biopsies demonstrates viable tumor, what is the recommended next step in management, and is there data to support that recommendation?