Case Report: Rectourethral fistula, a rare complication following prostate cancer external beam radiation and brachytherapy

Background: Prostate cancer is the second most common cancer in men; 11% of men will receive a diagnosis of prostate cancer throughout their lifetime. In most cases, the cancer is asymptomatic and localized. Because of its indolent growth, many treatment modalities are available including radical prostatectomy, external beam radiation, brachytherapy, cryotherapy, and thermal ablation. Post-operative complications of these procedures include erectile dysfunction, urinary incontinence, urethral stenosis, and rectourethral fistula (RUF). RUF is an abnormal connection allowing passage of contents between the bladder and rectum. This rare and serious complication typically presents in older patients after transurethral resection of the prostate or post-radiation biopsy and requires extensive surgical salvage or diversion to repair. Case Presentation: A 49-year-old male with a past medical history of erectile dysfunction and elevated was diagnosed with prostate cancer following a biopsy showing Gleason Score 3+4=7 in 1/12 cores and Gleason 6 in 1/12 cores. He was referred to oncology and subsequently underwent external beam radiotherapy and brachytherapy with radiation seed placement. One year later, he presented to the clinic with pneumaturia, urinary diarrhea, and incontinence per urethra. His presentation suggested an RUF confirmed by cystoscopy which showed a posterior urethral tear immediately distal to the external urethral sphincter at the 7 o'clock position. The patient was referred for imaging and surgical evaluation for further management. Conclusion: Here we present the rare complication of rectourethral fistula formation in a young patient after external beam radiation in conjunction with brachytherapy.