Epidemiology of Cancers of the Kidney in an Australian Population

Abstract

Background. Kidney cancer has a high incidence in Australia by world standards but has attracted little public health attention because of its low ranking among other cancers as a cause of death. Incidence, mortality and survival trends were investigated in this study for an Australian population and cancer control opportunities considered. Design. Age-standardized incidence and mortality rates were analyzed by broad age category using data from an Australian cancer registry. Disease-specific survivals were analyzed using the Kaplan-Meier product limit estimate and multivariable Cox proportional hazards regression. Results. Incidence rates approximately doubled during 1980-2008, with large increases affecting both sexes. Increases were more evident for renal cell and other histology types occurring predominantly in adulthood than childhood nephroblastomas. The male to female incidence ratio approximated 2:1 but decreased over time and was lower in younger than older age groups. The increase in mortality rate was smaller (at 25%) and higher in males (at 36%) than females (at 7%). Mortality increases were restricted to the age range of 70 years and over. Five-year survivals increased from 47% for 1980-84 to 66% for 2000-08 and multivariate predictors of high case fatality were older age at diagnosis and less recent diagnostic period. Country cases had lower survivals than metropolitan cases, although the difference was small. Conclusions. Increases in mortality were smaller than incidence increases, evidently due to offsetting increases in case survival, and did not affect the younger age groups. Further reductions in tobacco smoking and reducing the prevalence of obesity will be important to prevent renal cell carcinomas. Molecular research is advocated to develop targeted therapies and potentially, an effective screening technology. Cancer registries need to routinely publish their data by histology type to enable more detailed global trend analyses. Population registries also need to record stage of cancer at diagnosis to facilitate interpretation of changes in survival.