En Bloc Versus Conventional Resection of Primary Bladder Tumor (eBLOC): A Prospective, Multicenter, Open-label, Phase 3 Randomized Controlled Trial.

BACKGROUND

En bloc transurethral resection of the bladder (eTURB) might improve the surgical management of non-muscle-invasive bladder cancer (NMIBC) in comparison to conventional TURB (cTURB).

OBJECTIVE

To evaluate whether eTURB is superior to cTURB in resection of NMIBC and specimen retrieval.

DESIGN, SETTING, AND PARTICIPANTS: This was a randomized, multicenter trial in patients with up to three cTa-T1 NMIBC tumors of 1-3 cm in size, who were enrolled from January 2019 to January 2022.

INTERVENTION

Participants were randomized 1:1 to undergo eTURB (n = 192) or cTURB (n = 192).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was the prevalence of detrusor muscle (DM) in the specimen retrieved. Secondary endpoints included bladder perforation, persistent disease at second-look TURB, positive lateral resection margin, positive deep resection margin, operation time, perforation rate, obturator reflex, conversion from eTURB to cTURB, recurrence-free survival, and disease recurrence at 3 mo.

RESULTS AND LIMITATIONS

A total of 384 patients were randomized to undergo eTURB or cTURB. A total of 452 tumors were resected and analyzed for the primary outcome. eTURB was superior to cTURB in retrieval of DM (80.7% vs 71.1%; mixed-model p = 0.01). Bladder perforation (5.6% vs 12%; difference -6.4%; 95% confidence interval [CI] -12.2% to -0.6%) and obturator reflex (8.4% vs 16%; difference -7.6%; 95% CI -14.3% to -0.9%) were less frequent in the eTURB arm than in the cTURB arm. Operation time did not differ between the two techniques (26 min, interquartile range [IQR] 20-38 for eTURB vs 25 min, IQR 17-35 for cTURB; difference 1 min, 95% CI -25.9 to 4.99). Second-look TURB was performed in 24 patients in the eTURB arm and 34 in the cTURB arm, with no difference in the rate of residual papillary disease (pTa/pT1: 56% vs 55.9%; difference 0.1%, 95% CI -25.5% to 25.7%). At median follow-up of 13 mo (IQR 7-20), 18.4% of the patients in the eTURB arm and 16.7% in the cTURB arm had experienced bladder cancer recurrence (Cox hazard ratio 0.87, 95% CI 0.49-1.52; p = 0.6).

CONCLUSIONS

In patients with clinical NMIBC with up to three tumors of 1-3 cm in size, tumor removal via eTURB resulted in a higher rate of DM in the pathologic specimen in comparison to cTURB. Moreover, eTURB was associated with lower frequency of obturator reflex and bladder perforation than cTURB was. While improving on the quality indicators for NMIBC, the long-term differential oncologic benefits of eTURB remain uncertain.

PATIENT SUMMARY

We compared two techniques for removal of bladder tumors and found that tumor removal in a single piece, called en bloc resection, provides a better-quality specimen for pathology analysis and fewer complications in comparison to the conventional method. This trial is registered at ClinicalTrials.gov as NCT03718754.