Immunotherapy-Induced Rectovaginal Fistula After Prior Reirradiation for Recurrent Cervical Cancer in a Pelvic Lymph Node

A 48-year-old woman received a diagnosis of American Joint Committee on Cancer stage IIIB (cT1b2N1M0), International Federation of Gynecology and Obstetrics stage IB2 cervical squamous cell carcinoma. She received concurrent weekly cisplatin and 3-dimensional conformal radiation therapy (4-field box) to the whole pelvis (including the common iliac nodes) to a dose of 45 Gy in 25 fractions, followed by a sequential boost of 9 Gy in 5 fractions to the involved 3- × 2-cm left external iliac lymph node (total dose 54 Gy), and intracavitary brachytherapy using tandem and ovoids to a total dose of 28 Gy in 4 fractions prescribed to the cervical high-risk clinical target volume (defined on computed tomography [CT] and magnetic resonance imaging [MRI]).