Gakis G, et al. BJU Int 2020.
OBJECTIVE: To determine whether transurethral en bloc submucosal hydrodissection of bladder tumours (TUEB) improves the quality of the resection compared to conventional transurethral resection (TURBT) in patients with NMIBC.
PATIENTS AND METHODS: A randomized, multicentre trial (HYBRIDBLUE) was conducted in a superiority design. Six German academic centres participated between 09/2012 and 08/2015. 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 which 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: One hundred-and-fifteen 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=0.0059) in the conventional group. R0 was confirmed in 30/56 TUEB-patients (57%) and 5/59 TURB-patients (9%; p<0.0001). No complications of grade III or higher were observed in both arms. At 3 and 12 months, 3 and 19 patients recurred in the TUEB group versus 7 and 11 patients in the TURBT group, respectively (p=0.33/p=0.08).
CONCLUSIONS: In this randomized study, TUEB was shown to be clinically safe regarding perioperative endpoints. An adequate histopathological assessment concerning muscle-invasion was significantly better assessable in the TUEB arm compared to standard TURBT. This finding inherits the clinical potential of reducing the rate of early re-resections. Yet, a larger study with RFS as primary endpoint is needed to assess the oncological efficacy between both techniques.