Randomized Study of Short-time Continuous Saline Irrigation After Transurethral Resection in Non-muscle Invasive Bladder Cancer.

Background/aim: To investigate the efficacy and safety of short-time continuous saline bladder irrigation (S-CSBI) compared to long-time CSBI (L-CSBI) after transurethral resection of bladder tumor (TURBT) in non-muscle invasive bladder cancer (NMIBC).

Patients and methods: Between 2016 and 2021, 323 patients with suspected primary NMIBC based on cystoscopic appearance were enrolled. Patients were randomly allocated to receive S-CSBI (3 hours) or L-CSBI (overnight) after TURBT. Patients with the highest risk NMIBC and muscle-invasive bladder cancer were excluded. The primary endpoint was the 2-year recurrence-free survival (RFS) rate for S-CSBI, which was tested for non-inferiority. A difference of 15% in the 2-year RFS rate (60%) was defined as the non-inferiority margin for comparing the long-time CSBI.

Results: A total of 230 patients (110 in the S-CSBI group and 120 in the L-CSBI group) remained for the per-protocol analysis after exclusion. The 2-year RFS rates for S-CSBI and L-CSBI were 70.5% [95% confidence interval (CI)=60.9-78.2] and 70.5% (95%CI=61.4-77.9), respectively. The 95%CI for S-CSBI was above the lower non-inferiority limit of 60%, confirming the non-inferiority of S-CSBI to L-CSBI. The intention to treat analysis also demonstrated the non-inferiority of S-CSBI. In terms of adverse events, no severe systemic toxicities were observed in either group, hematuria grade IIIa was higher in the S-CSBI group, although not statistically significant.

Conclusion: S-CSBI after TURBT was non-inferior to L-CSBI with regard to the 2-year RFS rate. S-CSBI is easy to administer, especially in day surgery, and may be a treatment choice for patients with NMIBC.