Prospective non-randomized comparison of transurethral laser en bloc resection vs. conventional resection of bladder tumors larger than 3 cm

BACKGROUND: En bloc resection of bladder tumor (ERBT) is an established surgical treatment method for patients with non-muscle invasive bladder cancer (NMIBC) in tumors less than 3 cm. Data regarding the efficacy and safety of ERBT on larger than 3 cm tumors are sparse and its efficacy compared to conventional transurethral resection (TURBT) remains unclear. The aim of this study was to prospectively compare the feasibility, safety and oncological outcomes of laser (Tm-fiber) ERBT and TURBT in patients with primary bladder lesions ≥3 cm. METHODS: A cohort of 45 patients who underwent surgery for primary NMIBC between February 2018 and March 2022 was collected prospectively. There was no randomization. All procedures were performed by two experienced surgeons. Inclusion criteria were as follows: age >18 years, primary Ta or T1 bladder tumor with a diameter of ≥3 cm, no more than 3 tumors and no history of upper tract urothelial carcinoma. Exclusion criteria were carcinoma in situ or invasion into muscle layer (≥T2). ERBT was performed with thulium fiber laser (IPG, Russia). Primary endpoints included efficacy with recurrence-free survival (RFS) at 3, 6 and 12 months. Secondary endpoints were safety parameters, perioperative data and specimen quality (the presence of muscle layer in specimens). RESULTS: Twenty-eight patients underwent laser ERBT and 17 conventional TURBT. The location and size of the tumors were comparable in both groups. The success rate was 93.3% in the ERBT group with two cases of conversion from ERBT to TURBT. Detrusor muscle was present in 92.8% patients in the ERBT group versus 70.5% in the TURBT group (P=0.04). Obturator nerve reflex was observed only in the TURBT group: 17.6% vs. 0.0% (P=0.02). The frequency of other complications was comparable between the two groups. RFS was not statistically different between the two methods at 3 (93.9% vs. 94.1%, P=0.87), 6 (89.3% vs. 82.3%, P=0.5) and 12 months (89.3% vs. 70.6%, P=0.11). CONCLUSIONS: Laser ERBT is a feasible and safe procedure to manage bladder tumors larger than 3 cm. While it seems safer than TURBT, its effect on efficacy remains to be assessed in larger trials.