PurposeThe advantages of en bloc resection of bladder tumors (ERBT) over transurethral resection of bladder tumors (TURBT) in terms of patient prognosis are not yet clear, and there are some technical limitations. We aimed to compare the tumor recurrence in non-muscle invasive bladder cancer (NMIBC) patients with tumor diameter ≥ 3 cm undergoing either TURBT or thulium laser ERBT.MethodsThe patients included were those diagnosed with NMIBC based on pathological confirmation and underwent TURBT or modified thulium laser ERBT in the Department of Urology at Tongji Hospital from 2019 to 2024. The patients’ medical records were meticulously collected and postoperative follow-up was diligently conducted by trained personnel. Recurrence-free survival curves were generated utilizing the Kaplan–Meier method, and group comparisons were performed using the log-rank trend test. To minimize biases, we employed stratified survival analysis, alongside univariate and multivariate Cox regression analysis.ResultsThis study included a total of 396 patients with NMIBC, with 214 undergoing TURBT and 182 undergoing ERBT. For all patients, there was no significant difference (P = 0.180) in RFS between the TURBT and ERBT groups. For patients with tumor diameter ≥ 3 cm, stratified analysis revealed that the RFS of the ERBT group was significantly better than that of the TURBT group (P = 0.033). However, in patients with tumor diameter < 3 cm, there was no significant difference (P = 0.150) between the two groups. Univariate (HR: 0.52, 95% CI 0.28–0.96, P = 0.036) and multivariate (HR: 0.49, 95% CI 0.25–0.93, P = 0.031) Cox analyses revealed that ERBT was an independent protective factor for recurrence in NMIBC patients with tumor diameter ≥3cm.ConclusionThis study found that thulium laser ERBT may offer advantages in managing NMIBC patients with tumor diameters ≥ 3 cm. This could potentially drive the clinical application of thulium laser ERBT.Trial registrationProtocol was registered at Chinese Clinical Trial Register (ChiCTR) with number ChiCTR2000035407 on 12 August 2020.