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

Abstract

Background and objective: 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). The objective of this study is to investigate whether ERBT could improve the 1-yr recurrence rate of NMIBC, as compared with SR.

Methods: A multicentre, randomised, phase 3 trial was conducted in Hong Kong. Adults with bladder tumour(s) of ≤ 3cm were enrolled from April 2017 to December 2020, and followed up until 1 yr after surgery. Patients were randomly assigned to receive either ERBT or SR in a 1:1 ratio. 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.

Key findings 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 and clinical implications: In patients with NMIBC of ≤ 3cm, ERBT resulted in a significant reduction in the 1-yr recurrence rate when compared with SR. The study results support ERBT as the first-line surgical treatment for patients with bladder tumours of≤ 3cm.

Keywords: Bladder cancer; En bloc resection; En bloc resection of the bladder tumour; Non–muscle-invasive bladder cancer; Transurethral resection of bladder tumour.