Transurethral En Bloc Resection Versus Standard Resection of Bladder Tumour: A Randomised, Multicentre, Phase 3 Trial.

ABSTRACT

BACKGROUND: Conventionally, standard resection (SR) is performed by resecting the bladder tumour in a piecemeal manner. En bloc resection of the bladder tumour (ERBT) has been proposed as an alternative technique in treating non-muscle-invasive bladder cancer (NMIBC). OBJECTIVE: To investigate whether ERBT could improve the 1-yr recurrence rate of NMIBC, as compared with SR. DESIGN, SETTING, AND PARTICIPANTS: A multicentre, randomised, phase 3 trial was conducted in Hong Kong. Adults with bladder tumour(s) of ≤3 cm were enrolled from April 2017 to December 2020, and followed up until 1 yr after surgery. INTERVENTION Patients were randomly assigned to receive either ERBT or SR in a 11 ratio. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was 1-yr recurrence rate. A modified intention-to-treat analysis on patients with histologically confirmed NMIBC was performed. The main secondary outcomes included detrusor muscle sampling rate, operative time, hospital stay, 30-d complications, any residual or upstaging of disease upon second-look transurethral resection, and 1-yr progression rate. RESULTS AND LIMITATIONS: A total of 350 patients underwent randomisation, and 276 patients were histologically confirmed to have NMIBC. At 1 yr, 31 patients in the ERBT group and 46 in the SR group developed recurrence; the Kaplan-Meier estimate of 1-yr recurrence rates were 29% (95% confidence interval, 18-37) in the ERBT group and 38% (95% confidence interval, 28-46) in the SR group (p = 0.007). Upon a subgroup analysis, patients with 1-3 cm tumour, single tumour, Ta disease, or intermediate-risk NMIBC had a significant benefit from ERBT. None of the patients in the ERBT group and three patients in the SR group developed progression to muscle-invasive bladder cancer; the Kaplan-Meier estimates of 1-yr progression rates were 0% in the ERBT group and 2.6% (95% confidence interval, 0-5.5) in the SR group (p = 0.065). The median operative time was 28 min (interquartile range, 20-45) in the ERBT group and 22 min (interquartile range, 15-30) in the SR group (p < 0.001). All other secondary outcomes were similar in the two groups. CONCLUSIONS: In patients with NMIBC of ≤3 cm, ERBT resulted in a significant reduction in the 1-yr recurrence rate when compared with SR (funded by GRF/ECS, RGC, reference no. 24116518; ClinicalTrials.gov number, NCT02993211). PATIENT SUMMARY: Conventionally, non-muscle-invasive bladder cancer is treated by resecting the bladder tumour in a piecemeal manner. In this study, we found that en bloc resection, that is, removal of the bladder tumour in one piece, could reduce the 1-yr recurrence rate of non-muscle-invasive bladder cancer.