The Use of Circulating Tumor Cells in T1 Stage Non-muscle Invasive Bladder Cancer: A Systematic Review and Meta-Analysis.

Non-muscle invasive bladder cancer (NMIBC) presents substantial variability in clinical outcomes, especially in high-grade T1 cases, which exhibit high recurrence and progression rates. Circulating tumor cells (CTCs) have emerged as a potential biomarker for cancer prognosis, with evidence linking CTC positivity to poor outcomes in various cancers. In bladder cancer (BC), studies suggest that CTC presence correlates with advanced tumor stage and treatment response, but findings are inconsistent. This study aims to clarify the association between CTC positivity and recurrence and progression to muscle invasiveness in BC. A comprehensive search was conducted using PubMed, SciVerse Scopus, Google Scholar, and the World Health Organization International Clinical Trials Registry Platform databases up to August 2024. This study focuses on assessing the predictive ability of CTCs for NMIBC recurrence and upstaging after transurethral resection of bladder tumor (TURBT). A total of 5 studies were included. Four of the 5 studies found a significant relationship between CTCs and recurrence after TURBT. The hazard ratio (HR) for recurrences was available in 5 studies, and the estimated pooled odds ratio (OR) predicted the value of recurrences for CTC- positive OR = 2.68 (95% CI: 2.11-3.25; P < .001; fixed-effect). Four studies provided data on disease progression from T1 to T2 after TURBT with an overall HR of 3.36 (95% CI: 2.68-3.25). Circulating tumor cells enhance prognostic accuracy and therapeutic strategies in NMIBC, particularly in high-risk cases. Further studies should address molecular subtype stratification and evaluate systemic chemotherapy for CTC-positive patients.