To report 8 cases of rectourethral fistula (RUF) in patients treated with high-intensity focused ultrasound (HIFU) for either localized or locally recurrent prostate cancer (PCa).

A retrospective analysis of 363 consecutive patients with PCa who underwent HIFU from 2002 to 2010 was done. One HIFU session was performed in 341 patients with localized PCa. Two HIFU sessions were performed in 22 patients. Salvage HIFU was performed in 22 patients after radiotherapy.

A total of 8 patients (2.2%) developed RUF. Their mean age was 69.38 ± 6.19 years (range 61-78). The mean follow-up was 50.45 ± 25.07 months (range 25 to 84). The mean interval between HIFU and the development of RUF was 3 ± 0.93 weeks (range 1-4). RUF occurred within 4 weeks after 1 HIFU session (n = 4; 1.17%), 4 weeks after a repeated HIFU session (n = 3; 13.63%), and 3 weeks after salvage HIFU (n = 1; 4.54%). The mean fistula size was 9 ± 7.13 mm (range 3-25). Conservative treatment failed in all patients. Of the 8 patients, 4 underwent radical prostatectomy, with an omentum flap interposition, 3 received a gracilis interposition flap, performed transanally because of a small lesion (<10Ch) or perineally, and 1 underwent radical prostatectomy, rectal resection, and creation of a colonic J-pouch.

The results of our study have shown that RUF is a rare, but severe, complication after 1 HIFU session (1.17%) for localized PCa. The occurrence of RUF after salvage HIFU (4.5%) and repeated HIFU sessions (13.63%) was markedly elevated. Spontaneous closure of RUF will not occur, requiring major abdominal surgery for definitive repair.