Approximately 25 % of bladder cancer is muscle-invasive at the time of diagnosis (muscle-invasive bladder cancer [MIBC]) (van der Heijden et al., 2025), with a survival of approximately 50 % at 5-year follow-up, regardless of the treatment modality (Martini et al., 2020). Radical cystectomy (RC), following neoadjuvant therapy, is currently the most common approach for patients with MIBC (van der Heijden et al., 2025). Despite advances in surgical techniques and perioperative management, RC is still characterized by high rates of perioperative complications (Hladun et al., 2022, Parekh et al., 2018). Additionally, as a result of surgery and urinary diversion, patients often experience a reduction in quality of life (QoL) (Yang et al., 2016). Therefore, alternative treatment options emerged for frail patients not able to withstand such a physically demanding surgery, as well as for those who wish to preserve their bladder. One of these therapeutic alternatives is trimodal therapy (TMT) which combines transurethral resection of the bladder tumor (TURBT), radiotherapy, and chemotherapy. TMT aims to achieve effective oncological outcomes while maintaining bladder function and QoL for selected patients.

However, the absence of robust randomized controlled trials (RCTs) has led to ongoing uncertainty regarding the efficacy of TMT compared to RC in terms of oncological outcomes. As a result, the integration of TMT into routine clinical practice remains limited (Tang et al., 2024). Some studies have reported conflicting findings, with certain analyses suggesting superior oncological outcomes with RC over TMT. A key reason for these discrepancies may be the presence of differences in baseline patient characteristics, which can be accounted for through propensity matching. Nevertheless, if differences in oncological outcomes persist even after propensity matching, explanations could include true treatment superiority or biases related to follow-up duration, such as lead-time bias, imbalanced censoring, or informative censoring. To date, no meta-analysis has systematically assessed the potential impact of informative censoring (IC) as a source of bias in studies comparing the oncological outcomes of TMT and RC (Ding et al., 2020, Ditonno et al., 2024, Matsukawa et al., 2024). Specifically, IC occurs when dropout rates between study arms are imbalanced in a non-random manner due to unaccounted factors, resulting in loss of information. In the context of TMT and RC, both treatments are typically provided at referral centers, and patients with frailty, comorbidities, or complications may be lost to follow-up if they are unable to return to the center where they were treated.

This study aims to systematically review and conduct a meta-analysis to evaluate the risk of informative censoring in studies comparing TMT and RC.