A Systematic Review on the Current Landscape of T1 Bladder Cancer Substaging

To conduct a systematic review on the current state of T1 bladder tumor substaging. These neoplasms display significant heterogeneity in oncological behavior and prognosis, leading to the proposal of various substaging methods. Our aim was to investigate the potential diagnostic and prognostic value of substaging in stage T1 bladder cancer for better oncologic outcomes.

A literature search using MEDLINE, EMBASE and Cochrane Library databases was conducted in March 2024 to identify relevant studies on T1 urothelial bladder cancer staging. A systematic review of included articles was performed following the PRISMA guideline statement. Literature search was conducted in English.

Overall, 63 studies published between 1990 and 2024 were included for final review including a total number of 8328 bladder tumor patients subject to T1 substaging. Various substaging methods have been developed, broadly classified into histometric (anatomy-based) and micrometric (semiquantitative) techniques. Advanced stages have been consistently associated with worse prognosis and need for a more radical therapeutic approach. A standardized, validated, unified substaging report system is lacking.

T1 substaging is a strong predictor of oncologic outcomes. Micrometric methods seem to be more reproducible and precise than histometric techniques in terms of feasibility and prognostic value. Standardization and validation of the technique could potentially enhance the bladder cancer treatment algorithm.