A comparative analysis of variant histology and urothelial bladder cancer following radical cystectomy

To analyze the prevalence of variant histology bladder cancer subtypes and compare survival and oncological outcomes following radical cystectomy, in urothelial and variant histology cohorts, at a high-volume Australian center.

A five-year retrospective cohort study, including 82 patients at a tertiary center in Queensland, Australia. Inclusion criteria comprised patients over 18 years old with localized high-risk bladder cancer and who underwent open cystectomy plus ileal conduit, with curative intent. Exclusion criteria included metastatic disease, an indication other than malignancy and treatment with palliative intent. Statistical analysis was performed using R version 4.4.1, with statistical significance reported at p < 0.05.

Variant histology comprised 26% of the study cohort with a greater proportion of highly aggressive VH subtypes observed in the data compared to current literature. On multivariable analysis, VH was not associated with a higher risk of mortality. However, muscle-invasive disease and positive lymph nodes were independently associated with a significant risk of mortality (P = 0.009 and P = 0.048, respectively). Within the VH bladder cancer group, there was a greater proportion (62%) found to be stage > T1 post-cystectomy, compared to the urothelial group (41%).

This is the only Australian study examining outcomes post-radical cystectomy across multiple VH subtypes. Highly aggressive subtypes (micropapillary, plasmacytoid, sarcomatoid) were over-represented in our cohort. Improved recognition of VH guides multidisciplinary decision-making while a standard of care is yet to be established. Multicentered Australian registries with long-term follow-up are needed to enhance statistical analysis and evaluate the impact of variant histology on treatment outcomes.