Assessing risk stratification in Bacillus Calmette-Guérin-treated high-grade Ta nonmuscle-invasive bladder cancer patients

Abstract

Purpose: According to European Association of Urology (EAU) guidelines, nonmuscle-invasive bladder cancer (NMIBC) is stratified by pathological stage and three clinical risk factors (age >70, size >3 cm, multiple lesions). High-grade (HG) Ta can be categorized as intermediate-risk (IR) or high-risk (HR). However, the 2021 EAU stratification is based on non-BCG-treated patients. This study investigated the predictive value of EAU risk groups and factors in TaHG treated with BCG.

Methods: We retrospectively reviewed NMIBC patients treated with BCG from 2005 to 2022. Patients were stratified by EAU 2021 risk groups. The primary endpoint was HG recurrence-free survival (RFS).

Results: Among 163 TaHG patients, 84 (54%) had one risk factor, 40 (23%) two, and 8 (4%) three. According to EAU 2021, 71% (115) were IR and 29% (48) HR. Median follow-up was 37 months (IQR 19-64). Three patients progressed to MIBC or M+. Three-year HG RFS was 84% (95% CI: 69-96), 80% (95% CI: 68-87), 83% (95% CI: 66-92), and 87% (95% CI: 38-98) for patients with 0, 1, 2, and 3 risk factors, respectively (P = 0.85). For IR and HR groups, 3-year HG RFS was 81% (95% CI: 76-90) and 84% (95% CI: 68-92) (P = 0.97). At Cox regression analysis, neither the number of risk factors nor HR classification was a predictor of HG recurrence (P = 0.9).

Conclusions: Progression to MIBC was rare in our real-world cohort of BCG-treated TaHG NMIBC, while HG recurrence rates mirrored those of T1HG cases. Neither the EAU 2021 risk groups nor individual clinical RFs predicted HG recurrence effectively. Development of recurrence-based risk models for TaHG NMIBC is therefore warranted.

Keywords: AUA; BCG; Bladder cancer; EAU 2021 guidelines; High-grade; IBCG; NMIBC; Risk categories; Ta.