The Impact of Histological Variants on Oncological Outcomes in Patients with Muscle Invasive Bladder Cancer Treated with Radical Cystectomy.

Objective: Bladder cancer is a heterogeneous entity characterized by a wide range of different morphologies. The aim of this study was to investigate the prognostic effect of bladder tumor with variant histology that is treated with radical cystectomy on oncological outcomes.

Methods: One hundred eighty-six patients who underwent radical cystectomy between September 2001 and June 2020 were included in the study. The patients were divided into 2 groups variant histology group (n = 54) and transitional cell cancer group (n = 132). Clinicopathologic data were compared between the two groups.

Results: The groups were similar in terms of demographic characteristics. In the mul- tivariate analysis of cancer-specific survival in transitional cell cancer against variant histology, high-grade detection of primary transurethral bladder tumor pathology, cystectomy pT, cystectomy positive lymph node, and positive surgical margin in cys- tectomy were determined to be statistically significant. Diagnosis of pT2 and high grade of primary transurethral bladder tumor pathology, cystectomy ≥ pT3, cystec- tomy positive lymph node, and positive surgical margin in cystectomy were statis- tically significant in multivariate analysis of overall survival. Cancer-specific survival time was estimated at 65.1 ± 8.3 months for variant histology and 134.2 ± 10.4 months for transitional cell cancer (P=.004). The estimated overall survival time was 61.9 ± 8.0 months in variant histology and 119.0 ± 9.8 months in transitional cell cancer (P = .014).

Conclusion: Pathological features and prognosis of bladder cancer with variant histol- ogies are worse than those of pure urothelial bladder cancer. Overall survival and can- cer-specific survival are shorter in bladder cancer with variant histology than in pure urothelial bladder cancer. Following the diagnosis of variant histology in transurethral bladder tumor, poor prognosis must be considered in the treatment plan.