Aim: Mortality among patients with bladder cancer is usually reported to be higher for women than men, but how the risk differs and why remain largely unexplained. We also described gender-specific differences in survival for patients with bladder cancer and estimated to what extent they can be explained by differences in T-stage distribution at the first diagnosis.
Methods: The present study comprised all 15,129 new cases of histologically verified invasive and non-invasive urothelial carcinoma of the urinary bladder diagnosed between 1997 and 2011 as registered in the Cancer Registry of Norway. Gender-specific excess mortality risk rates and risk ratios were calculated based on a flexible parametric relative survival model adjusting for T-stage and age, allowing the effect of gender to vary over time. We also present gender-specific relative survival curves for different T-stage patterns adjusted for age.
Results: Risk rates were significantly higher for women than men up to 2 years after bladder cancer diagnosis, particularly for muscle-invasive cancers. Thereafter, risk rates appeared to be higher in men. Adverse T-Stage distribution in women explained half of the unfavourable survival difference in female patients 2 years after diagnosis.
Conclusion: The common view of worse bladder cancer prognosis in women than in men needs to be revised. Norwegian women have a less favourable prognosis solely within the first 2 years after diagnosis, particularly when diagnosed with a muscle-invasive tumour; parts of this discrepancy can be attributed to more severe initial diagnoses in women.
Keywords: Bladder cancer; Gender; Gender difference; Prognosis; Survival; Urothelial cancer.
Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.