Transurethral resection of bladder tumor (TURBT) is the cornerstone procedure in the diagnosis and treatment of bladder cancer but is associated with a spectrum of intraoperative bladder injuries ranging from minor mucosal tears to major perforations. Currently, there is no standardized intraoperative classification system specifically designed to grade and report these injuries during TURBT.

This study aims to apply the Bladder Injury Classification System for Endoscopic Procedures (BICEP) to TURBT in order to systematically classify intraoperative bladder injuries, evaluate their management, and explore their association with perioperative and early postoperative outcomes.

Transurethral resection of bladder tumors (TURBT) is a fundamental endourological procedure for the diagnosis, staging, and initial management of bladder cancer. Despite its widespread use and standardized oncological objectives, TURBT is associated with a broad spectrum of intraoperative bladder injuries, ranging from minor mucosal lesions to major bladder perforations or ureteral orifice injuries. Currently, intraoperative bladder injuries during TURBT are inconsistently defined and reported, often being retrospectively captured only through postoperative complication grading systems, which limits objective comparison between techniques, surgeons, and centers.

This study is designed as an observational patient registry aiming to systematically evaluate intraoperative bladder injuries occurring during TURBT using the Bladder Injury Classification System for Endoscopic Procedures (BICEP). The BICEP classification is an anatomically based intraoperative grading system that categorizes bladder injuries according to depth, severity, and required management, allowing standardized real-time documentation of endoscopic injuries. By applying this framework to TURBT, the registry seeks to establish a reproducible and clinically meaningful method for injury reporting in oncologic endourology.

The registry will prospectively collect perioperative data from patients undergoing TURBT, including tumor characteristics, operative setting, energy modality, resection technique, intraoperative events such as obturator reflex, and bleeding severity. Intraoperative bladder injuries will be classified using the predefined BICEP categories, and injury timing, anatomical location, confirmation methods, and management strategies will be recorded in a structured manner. Postoperative clinical course data will be captured to allow assessment of early outcomes and short-term clinical impact.

This registry is implemented using a standardized electronic data capture system with predefined variable definitions and structured fields. Data quality is ensured through built-in range checks, mandatory fields for key variables, and internal consistency rules to minimize incomplete or conflicting entries. A detailed data dictionary defines each variable, its clinical meaning, coding structure, and acceptable value ranges to ensure uniform interpretation across participating centers. Source data for registry entries are derived from routine clinical documentation, including operative reports, anesthesia records, and postoperative follow-up notes.

Participating centers are instructed to enter consecutive eligible cases to reduce selection bias and improve representativeness. Periodic data reviews are planned to assess completeness, logical consistency, and adherence to registry definitions. Data validation procedures include cross-checks between related variables (for example, injury grade and management strategy) to identify discrepancies. The registry is designed to be expandable, allowing future linkage with additional outcomes or long-term oncological follow-up modules if required.

Sample size is not fixed a priori, as the registry is designed to capture real-world practice patterns and complication profiles across centers. Accrual will continue until a sufficient number of cases is obtained to allow meaningful descriptive and comparative analyses of injury patterns and associated perioperative factors. Missing data will be handled using predefined categories (unknown, not applicable) and will be reported transparently in analyses.

Statistical analysis will primarily focus on descriptive statistics to characterize injury incidence and severity, followed by exploratory analyses evaluating associations between intraoperative bladder injury grades and perioperative variables or early postoperative outcomes. Analytical methods will be aligned with the observational nature of the registry and hypothesis-generating intent of the study.

By establishing a structured and standardized registry for intraoperative bladder injuries during TURBT, this study aims to improve the quality of complication reporting, facilitate comparison between surgical techniques and energy modalities, and provide a foundation for future prospective validation studies and quality improvement initiatives in endourological oncology.

Inclusion Criteria:

• Adult patients aged 18 years or older
• Patients undergoing transurethral resection of bladder tumor
• Procedures performed for primary resection, re-resection, diagnostic, or staging purposes

Exclusion Criteria:

• Patients with incomplete intraoperative data regarding bladder injury assessment
• Patients who decline participation, if informed consent is required

The study population consists of adult patients undergoing transurethral resection of bladder tumors at participating centers. Participants are identified from consecutive cases in which intraoperative bladder injury assessment is performed and recorded using a standardized classification approach during the procedure.

De-identified individual participant data (IPD) will be available upon reasonable request for research purposes. Data will be shared following local ethics committee approval and execution of a data-use agreement. No direct patient identifiers will be shared. Data will include demographic variables, baseline assessments, operative details, postoperative outcomes, and follow-up measures collected in the registry.

De-identified individual participant data (IPD) and supporting documents will be available beginning 12 months after publication of the primary results manuscript and will remain available for a minimum of 5 years thereafter.

only qualified researchers with a methodologically sound proposal will be granted access. Requests must be reviewed and approved by the principal investigator and require completion of a data-use agreement. Access will be provided in de-identified format only and delivered via secure, password-protected electronic transfer. No direct identifiers or protected health information will be shared.