Poor survival of females with bladder cancer is limited to those aged 70 years or over: a population-wide linkage study, New South Wales, Australia

Abstract

Although men are diagnosed with bladder cancer (BC) with a rate three times higher than women, women experience poorer survival. The cause of this gender difference is not clear. The aim of this study was to investigate the discrepancy in survival from BC by gender and explore potential explanations for the difference using a population-wide linkage study. Using the New South Wales (NSW) Central Cancer Registry, all invasive BC cases diagnosed between 2001 and 2009 were identified. Records were linked to the NSW Admitted Patient Data Collection (APDC), to retrieve treatment details, and to the Registry of Births Deaths and Marriages and Australian Bureau of Statistics to obtain death details. A total of 5377 new cases of BC were identified. No differences were identified in the proportions of patients presenting at different stages between genders. However, disease-specific survival (DSS) was worse for females compared to males with localized and regional disease (P < 0.05). This difference was only apparent in individuals aged ≥70 years and no difference was identified in those younger. Multivariable Cox-regression analysis of the cohort of individuals aged ≥70 years revealed that stage, age, comorbidity, and sex remained independent variables (P < 0.05) predicting DSS. In a population wide analysis, females aged 70 years or more suffer worse DSS compared to males. The differences are not accounted for by stage at presentation or comorbidity and are independent of age. BC in postmenopausal females may be biologically more aggressive.