03:54 PM Abstract No. 417 Treatment of rectourethral fistulae after focal ablation for prostate cancer

Abstract

Purpose: Transrectal focal laser ablation (FLA) of prostate cancer in the MRI environment carries with it the risk of thermal damage to the rectal wall resulting in rectourethral fistula (RUF) formation with painful and/or prolonged cystoprostatitis. RUF's are treated surgically with temporary colonic diversion (colostomy) and flap interposition between the rectum and urethra which leaves the patient lifestyle limitations and often urinary incontinence. An alternative treatment for small RUF's is a conservative medical course including weeks of urinary catheterization. Materials: Out of 221 trans-rectal, MRI-guided FLA procedures for low risk prostate cancer, 9 patients (4.1%) developed symptoms of RUF such as anal urination, hematuria, pneumaturia and prolonged cystoprostatitis. Eight of the 9 patients (89%) had the RUF documented at urethrocystoscopy. The patients were treated with a combination of antibiotics, urinary catheter placement and anxiolytics for the stress of chronic urinary catheterization. Patients took oral vitamin supplements as well as stool softeners and fiber, all to promote healing. After 5 weeks of this conservative care, patients had a retrograde urethrogram to document closure of the RUF. Results: All 9 patients experienced symptoms of RUF about 1 week after FLA (mean 6.3 days). Seven (78%) of the 9 patients spontaneously healed after 5 weeks of catheterization and conservative care. One patient had a history of previous radiation therapy to the prostate and required surgical correction of the RUF after colonic diversion. Another patient required an additional 2 weeks of catheterization after the initial 5 weeks therapy failed to heal the RUF completely. Post-FLA T-1 weighted MRI sequences with contrast showed evidence of thermal damage to the rectum in 8 of 9 patients (89%) visible as an avascular linear zone of necrosis extending beyond the prostate capsule into the rectum. Conclusions: Post FLA RUF symptoms appear about one week post procedure and about 90% heal with conservative management lasting 5-7 weeks. Post FLA thermal necrosis in the rectum predicts RUF formation suggesting it could be treated expectantly.