Occurrence of both bladder and prostate cancer in five cancer registries in Belgium, The Netherlands and the United Kingdom

ObjectiveTo assess the occurrence of both bladder and prostate tumours in five well defined cancer registries.MethodsAnonymous data were provided from each cancer registry on all male bladder and prostate cancers (invasive and non-invasive). Poisson regression was used to model the rate of developing the second primary tumour and generated incidence rate ratios (RRs) with 95% confidence intervals.ResultsFor bladder cancer and prostate cancer as first diagnosis, there was an excess risk to develop the second neoplasm. The RR decreased with increasing age of the patients. No effect of the initial treatment of the first neoplasm was found.ConclusionThis analysis found an excess risk to develop prostate cancer in bladder cancer patients younger than 70 years and the first year of follow-up after the diagnosis of bladder cancer. This may be due to detection bias, although a common aetiology may also be present.