Based on large sample size studies at home and abroad, the prognosis of patients with non-muscular invasive bladder cancer in different sites undergoing transurethral bladder tumor resection was determined, providing important guidance for subsequent clinical treatment and surgical instrument development.

Background Most bladder cancers are non-muscle invasive bladder cancer (NMIBC), and transurethral resection of bladder tumors (TURBT) is the standard treatment. However, postoperative recurrence poses a challenge, and the influence of bladder tumor location on prognosis is unclear. This study aims to investigate how tumor location affects NMIBC patients' prognosis undergoing TURBT, and seeks optimal surgical approaches.

Methods Conducted a multicenter study, including Chinese NMIBC data from 15 hospitals (1996-2019) and SEER 17 registries (2000-2020). Analyzed patients initially diagnosed with NMIBC undergoing TURBT or partial cystectomy, excluding cases with lost follow-up or missing data. Studied overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS). Employed Kaplan-Meier, Cox regression, and propensity score matching to explore the association between tumor location and prognosis. Stratified populations were analyzed to minimize bias.

Findings This study, involving 118,477 NMIBC patients, highlighted tumor location as a crucial factor impacting post-TURBT prognosis. Anterior wall and dome tumors independently predicted adverse outcomes in both cohorts. For anterior wall tumors, Chinese cohort showed OS HR 4.35, p < 0.0001; RFS HR 2.21, p < 0.0001; SEER OS HR 1.10, p = 0.0001; DSS HR 1.13, p = 0.0183. Dome tumors displayed similar trends (Chinese NMIBC cohort OS HR 7.91, p < 0.0001; RFS HR 2.12, p < 0.0001; SEER OS HR 1.05, p = 0.0087; DSS HR 1.14, p = 0.0006). Partial cystectomy significantly improved dome tumor survival compared to standard TURBT (p < 0.01).

Interpretation This study reveal that NMIBC tumor location significantly influences TURBT treatment outcomes. Specifically, tumors in the anterior wall and bladder dome have worse post-TURBT prognosis. Compared to TURBT, partial cystectomy improves prognosis for bladder dome tumors. This study guides personalized treatment and prognosis management for NMIBC patients.

Inclusion Criteria:

1. Initially diagnosed with non-muscular invasive bladder cancer (NMIBC) who underwent TURBT or partial cystectomy.
2. The follow-up data of the patients were complete.
3. The tumor location information were complete.

Exclusion Criteria:

1. Patients with unknown survival time or missing tumor location information were excluded.
2. Exclude patients with missing pathological results.
3. Exclude patients who have had TURBT before.

This study utilized the Chinese NMIBC cohort as well as the SEER 17 registries cohort for its investigation. The Chinese NMIBC cohort contains data of patients between January 1996 and December 2019, at 14 institutions. SEER*Stat software (version 8.4.1.1) was used for collecting 17 registries cohort data on patients diagnosed with NMIBC between 2000 and 2020.