Urosymphyseal fistula after pelvic radiotherapy in a tertial referral centre - a rare entity with significant comorbidity requiring multidisciplinary management.

Objective: To report population-based clinical presentation and outcomes in patients with urosymphyseal fistula (USF) after pelvic radiotherapy (RT).
Patients and Methods: A retrospective chart review was performed in 33 consecutive patients diagnosed with suspicion of USF in a tertial referral center from 2014-2022 to ascertain information about diagnostic delay, clinical presentation, precipitating causes, treatments received and outcomes during the median 22 months follow-up. Out of 33 consecutive patients with suspicion of USF, one female with vesicovaginal fistula, one patient developing RT-associated bladder angiosarcoma, four patients with short follow-up (<3 months), and three patients that during chart review not were considered to have a USF were excluded.
Results: In all, 24 males with a median age of 77 years were diagnosed with USF. Local pain was the predominating symptom in 17/24 (71%) patients. Endourologic manipulations preceded the diagnosis of USF in 16 patients. Five patients had a diagnostic delay of more than 3 months. At diagnosis, 20/24 patients had radiological signs of osteomyelitis, and five had a concomitant rectourethral fistula. Due to comorbidity, five patients were not amenable to any other interventions than urinary catheter or suprapubic tube in conjunction with long-term antibiotics, of which three died from infections related to the USF. Out of the remaining 19 patients receiving some form of urinary diversion, five had recurrent osteomyelitis, of which four did not undergo cystectomy in conjunction with surgery for the USF.
Conclusions: Urethral endourologic interventions in patients previously subjected to pelvic RT should be performed cautiously.