Ureteroenteric strictures following retrosigmoid vs. conventional ileal conduit – The MOSAIC study (The DaBlaCa‐16 study)

Objectives To evaluate the rate of left‐sided ureteroenteric strictures (UES) following robot‐assisted radical cystectomy (RARC) with a retrosigmoid ileal conduit compared to a conventional ileal conduit in a randomised controlled trial (RCT). Patients and Methods This multicentre, RCT included 303 patients undergoing RARC between May 2020 and August 2022. Patients were randomised to receive either a retrosigmoid or a conventional ileal conduit. Analyses were performed an intention‐to‐treat basis. Results Of the 149 patients randomised for the retrosigmoid ileal conduit, a total of 137 (92%) patients received the allocated conduit. In the control group, 150 of 154 (97.4%) patients underwent RARC and one patient was lost to follow‐up. At a median follow‐up of 754 days, the rate of left‐sided UES was 4.1% (six of 148) in the intervention group and 6.7% (10 of 149) in the control group ( P = 0.31). No significant differences were observed in postoperative creatinine clearance or metabolic complications, including vitamin B 12 deficiency and metabolic acidosis. Conclusion The rate of left‐sided UES was not significantly reduced with the retrosigmoid conduit compared to the conventional approach. However, the procedure was feasible without increased risk of metabolic complications and therefore may be a good alternative when extensive resection of the left ureter is needed.