The impact of histopathological evaluation at transurethral resection of bladder tumour on survival in radical cystectomy candidates

Objective: To evaluate the impact of discordant histological diagnoses between transurethral resection of bladder tumour (TURBT) and radical cystectomy (RC) on cancer-specific mortality (CSM) in patients with bladder cancer (BCa). Patients and Methods: We relied on a multi-institutional database collecting data of patients with BCa who underwent TURBT and subsequent RC from nine centres between 2000 and 2023. We tested concordance rates between TURBT and RC in detecting urothelial carcinoma of the urinary bladder (UCUB) as well as non-UCUB hystological subtypes, using RC as the reference standard. Concordance was defined as the agreement between a specific histological subtype identified both at TURBT and RC and evaluated according to Cohen's kappa coefficient. Subsequently, survival analyses consisted of Kaplan–Meier plots and multivariable Cox regression (MCR) models addressing CSM according to concordance between TURBT and RC (namely, concordant vs discordant). Results: Overall, 3160 patients were identified. Of these, 2762 (87%) harboured UCUB and 398 (13%) non-UCUB at TURBT vs 2481 (79%) UCUB and 679 (21%) non-UCUB at RC. There were 683 (21.6%) patients with a discordant diagnosis between TURBT and RC. The overall concordance in detecting non-UCUB subtypes was defined as fair concordance (Cohen's kappa coefficient: 0.32). In MCR models, a discordant diagnosis exhibited higher CSM relative to those with a concordant diagnosis (hazard ratio [HR] 1.3, 95% confidence interval [CI] 1.1–1.6; P = 0.002). In a sensitivity analysis including patients with UCUB not exposed to neoadjuvant chemotherapy, this survival disadvantage was even higher (HR 1.5, 95% CI 1.1–1.7; P = 0.04). Conclusions: A discordant histopathological diagnosis between TURBT and RC is associated with higher CSM rates, particularly in cases initially misdiagnosed as UCUB. However, we also observed a moderate concordance between TURBT and RC in identifying non-UCUB subtypes.