Enterovesical fistula is a rare complication of pelvic radiotherapy. Recurrent disease is the cause of fistulization in most patients. We identified 14 patients who developed enterovesical fistula in the absence of tumor recurrence. These women were at high risk for radiation morbidity due to prior surgery, pelvic inflammatory disease, adjuvant hyperbaric oxygen, or locally high doses of radiotherapy caused by suboptimal geometry and technique. All patients underwent radiographic imaging including barium enema, intravenous pyelogram, and upper gastrointestinal study with small bowel follow-through. The range of radiation morbidity was great: some patients had small fistulae, others had extensive fistulization and radionecrosis. Six patients had colovesical fistulae, five had enterovesical fistulae, and three had fistulae involving both the small and large bowel. Twelve patients underwent 13 surgical procedures. Healing or successful repair of the fistula was achieved in 1 of 3 patients treated with diversion (loop colostomy), 2 of 4 patients treated with isolation of the fistulized bowel loop and urinary conduit, and 5 or 6 treated with bowel resection with or without urinary conduit. Two of three perioperative deaths occurred in the isolation group managed without urinary conduit and were related to ongoing sepsis. Surgical procedures which resect necrotic fistulized bowel and result in complete separation of the gastrointestinal and genitourinary tracts provided the best results in patients with radiation-induced enterovesical fistulae. CT scan of the abdomen and pelvis is recommended in the evaluation of the majority of patients with suspected enterovesical fistula.

Levenback, Gershenson, McGehee, Eifel, Morris, Burke, , , (1994). Enterovesical fistula following radiotherapy for gynecologic cancer. Gynecologic oncology, 1994 Mar;52(3):296-300. https://www.ncbi.nlm.nih.gov/pubmed/8157186