BCG Response and Oncological Outcomes in High Risk Nonmuscle Invasive Bladder Cancer Following Previously Treated Upper Tract Urothelial Carcinoma: A Propensity-Matched Analysis - Beyond the Abstract

Upper tract urothelial carcinomas (UTUC) are considered an uncommon malignancy.¹ Despite optimal treatment for the UTUC, metachronous bladder recurrences (M-NMIBC) can occur in 3-50% pr patients. Due to its rarity and the resultant lack of specific guidelines, patients with bladder recurrence following nephroureterectomy have historically been managed using treatment paradigms similar to those for primary bladder cancers (P-NMIBC), despite emerging evidence demonstrating inferior clinical outcomes compared to their lower tract counterparts.^2-4

Our study offers a compelling insight into a clinically relevant but underexplored domain: the effectiveness of Bacillus Calmette-Guérin (BCG) therapy in high-grade non-muscle invasive bladder cancer (NMIBC) occurring after prior treatment for UTUC. Through a rigorously designed propensity-matched analysis, we demonstrated that patients with M-NMIBC had significantly higher rates of BCG failure, intravesical recurrence, and progression to muscle-invasive disease compared to those with P-NMIBC. Almost half with M-NMIBC will have high grade bladder recurrences after BCG, with a quarter progressing to muscle-invasive or metastatic disease. The alarmingly high rates of disease recurrence and progression suggest that prior UTUC is not merely a historical footnote in a patient’s oncological journey, but rather an active contributor to subsequent treatment resistance and tumour aggressiveness in the lower tract. This work reinforces the growing understanding that urothelial tumours arising in different locations, though histologically similar, are biologically distinct entities.^5-6

(1A)

(1B)

(1C)

Our study’s most notable findings are the paradoxical observation that M-NMIBC tumours tend to be smaller and lower T staging, ostensibly because of early detection from routine surveillance cystoscopy, yet still had worse outcomes. This underscores the probable clonal relationship between UTUC and its subsequent metachronous bladder recurrences, supported by recent molecular studies identifying FGFR3 overexpression and immune-depleted tumour microenvironments in the M-NMIBC subgroup.^7-8 These molecular differences likely compromise BCG’s immune-mediated mechanism of action, suggesting a need for personalized therapeutic strategies.⁹

Clinically, these findings argue for a reassessment of standard BCG protocols in M-NMIBC patients and raise important questions regarding risk stratification. Should a history of UTUC prompt consideration of early radical treatment or alternate intravesical regimens? Should molecular profiling be routine in guiding therapy in such cases?

We hope to have shined a necessary spotlight on the unique clinical trajectory of M-NMIBC post-UTUC. Our findings not only challenge the one-size-fits-all paradigm of intravesical therapy but also support the integration of tumour biology into clinical decision-making. UTUC history should no longer be considered a background variable—it is, increasingly, a defining feature of bladder cancer behaviour and treatment response. Prognostic risk tables developed for high risk bladder tumour recurrence should emphasize a UTUC history, as it portends a poorer clinical outcome in addition to conventional clinicopathological features. More importantly, while we are witnessing a burgeoning body of evidence supporting bladder-preserving strategies for BCG-unresponsive disease, their clinical applicability and outcomes in M-NMIBC will need to be interpreted with caution.

1. Department of Urology, Singapore General Hospital.
2. Department of Urology, Duke University School of Medicine, Durham, NC, USA

References:

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