Sex differences in muscle-invasive bladder cancers: A study of a French regional population

Objectives: Although men have a higher risk of developing a bladder cancer, women appear to have a poorer prognosis and a more advanced stage at diagnosis. We performed a retrospective population-based study on muscle invasive bladder cancer (MIBC) using data from a cancer registry in a French department to compare overall and specific survival data according to sex. Material and methods: We included all patients living in the department of H & eacute;rault and diagnosed with MIBC between January 1, 2017 and December 12, 2019. Univariable and multivariable analyses were performed on all variables of interest. Results: We included 124 women and 432 men. There was no significant difference in age or stage at diagnosis according to sex. Squamous cell carcinomas were more common in women (P < 0.001). Cystectomy was more frequent in men than in women (50.7% vs 35.4%) (P = 0.0039). By multivariable analysis, the independent factors for being treated by cystectomy were sex (P = 0.004), age (P < 0.001) and stage (P < 0.001). Forty-seven percent of women received no treatment or palliative treatment. Overall mortality was 79% in women and 63.2% in men (P < 0.001). The median specific survival was 10.8 months in women and 32.7 months in men (P < 0.0001). By multivariable analysis, the independent risk factors for mortalitywere female sex (P = 0.047), cT4 stage (P = 0.005) and absence of cystectomy (P < 0.001). Conclusions: Our study shows that women are less often treated with cystectomy and have worse prognosis than men. The reasons for this gender difference are multifactorial.