The Institutional Review Board of the University of Tokyo approved the study protocol, including the use of an opt-out methodology to obtain informed consent (approval no. 3124). Participants were informed about the study using generally accessible contact information. Written informed consent was provided by participants who chose to take part in this study. All procedures followed appropriate guidelines.
The clinical database of the University of Tokyo Hospital was retrospectively reviewed to identify patients with end-stage HIC who underwent PC–CP or TC–IC between 2002 and 2020. Diseases were diagnosed and classified according to East Asian and European clinical guidelines for IC/BPS. 118
Cystectomy was considered for patients with end-stage HIC if their QOL was markedly impaired or if they had experienced significant complications in the upper urinary tract, such as persistent hydronephrosis and/or recurrent (defined as three times or more per year) pyelonephritis. The former was characterized by intractable and persistent bladder pain, extraordinarily frequent urination, or continued urinary leakage that could not be controlled by an indwelling urethral catheter. A thorough personal consultation was performed prior to surgery. Patients were informed of related risks, such as persistence/recurrence of symptoms, the need for CIC, the irreversibility of the procedure and body image of the stoma, and the risk of perioperative complications. All patients provided informed consent for cystectomy and the procedure, PC–CP or TC–IC.
The PC–CP procedure involved excision of the bladder wall while preserving the bladder neck and trigonal area with bladder augmentation using ileal segments. The TC–IC procedure consisted of simple cystectomy and ileal conduit formation, with urethrectomy in male patients, as indicated. TC–NB was not attempted because of the higher risks of complications and postoperative CIC.
Postoperative complications in both groups were monitored by assessing symptoms, by performing blood tests and urinalysis, by urine culture, by measurements of post-void residual urine, and by ultrasound scanning. Postoperative complications were managed by additional interventions, as needed. All operations were performed using an open approach by one of the four specialized urologists (YA, ANi, YI, YH) at our facility.
Assessment and evaluation
Symptoms were assessed using an 11-point numerical rating of pain intensity, with 0 indicating no pain and 10 indicating the worst pain imaginable. QOL scores were measured on a 7-grade QOL scale derived from the International Prostate Symptom Score, with 0 indicating an excellent QOL and 6 indicating a terrible QOL. OSSI/OSPI indices were assessed pre- and postoperatively in patients who underwent PC–CP alone, as questions on voiding frequency and urgency are inapplicable to patients who undergo TC–IC. Patients were closely monitored for anticipated complications, such as voiding difficulty necessitating CIC, hydronephrosis, and pyelonephritis. Hydronephrosis was graded according to the Society for Fetal Urology ultrasound grading system. 19 Patients’ overall satisfaction with surgical outcomes was assessed using a yes-or-no question 1 year after surgery or when complications were stabilized.
Symptom parameters before and after surgery in each group were compared by Wilcoxon signed rank tests, whereas symptom parameters in the two groups were compared by Wilcoxon rank sum tests. Categorical variables were compared using Fisher's exact tests. All statistical analyses were performed using JMP® software, version 14 (SAS Institute, Cary, NC, USA), with P-values <0.05 considered statistically significant.