Transurethral en bloc submucosal hydrodissection vs conventional resection for resection of non‐muscle‐invasive bladder cancer (HYBRIDBLUE): a randomised, multicentre trial

Objective To determine whether transurethral en bloc submucosal hydrodissection of bladder tumours (TUEB) improves the quality of the resection compared to conventional transurethral resection of bladder tumour (TURBT) in patients with non‐muscle‐invasive bladder cancer (NMIBC). Patients and Methods A randomised, multicentre trial (HYBRIDBLUE) was conducted with a superiority design. Six German academic centres participated between September 2012 and August 2015. Based on literature analysis, a sample size for accurate histopathological assessment concerning muscle invasion was assumed to be feasible in 50% (P0 = 0.5) of TURBT and 80% of TUEB cases. After pre‐screening of a total of 305 patients, participants were allocated to two study arms: Group I: hexaminolevulinate (HAL)‐guided TUEB; Group II: conventional HAL‐guided TURBT. The primary endpoint was the proportion of specimens that could be reliably evaluated pathologically concerning muscle invasiveness. Secondary endpoints included rates of histopathological completeness of the resection, muscularis propria content, recurrence, and complication rates. Results A total of 115 patients (TUEB 56; TURBT 59) were eligible for final analysis. Adequate histopathological assessment, which included muscularis propria content and tumour margins (R0 vs R1), was present in 48/56 (86%) TUEB patients compared to 37/59 (63%; P = 0.006) in the TURBT group. R0 was confirmed in 30/56 TUEB patients (57%) and five of 59 TURBT patients (9%; P