Geospatial co-distribution of human and canine urothelial cell carcinoma and associated environmental risk factors in Queensland, Australia

BACKGROUND AND AIM: Available evidence indicates that tumours in dogs and humans show a wide variety of biological and clinical similarities. Recent evidence suggests that environmental pollutants may contribute to increased risk of cancers of the urinary tract such as urothelial cell carcinoma (UCC) in humans and dogs. We hypothesised if such a relationship exists then urinary cancer incidence in humans could be spatially and temporally collocated with that of canine companion animals. METHOD: We used human UCC patient records for 4937 individuals and 170 dogs in Queensland, Australia from 2008 to 2018, retrieved from Cancer Data Queensland and from the VetCompass Australia and the University of Queensland’s pathology laboratory databases, respectively. Both human and canine data were aggregated to the postcode-level, using postcode of residence for humans and postcode of veterinary clinic for dogs. Climate and environmental exposures including precipitation, land surface temperature, model predictions of outdoor annual fine particulate matter ≤2.5μm (PM2.5) and nitrogen dioxide (NO₂) concentrations, and distances to cropland and industrial areas were linked to the postcodes. Cluster analysis of canine UCC incidence was performed using Anselin Local Moran's I and a statistical model of human UCC incidence was developed, taking into account environmental and climate factors, including PM2.5, NO2, precipitation, land surface temperature, and land use. RESULTS: Our results suggest that human UCC incidence is higher in postcodes surrounding clusters of high canine UCC incidence. The significance of this result is partly explained by environmental pollution factors. The findings of this study highlight significant spatial variation in both human and canine UCC incidence are associated with common environmental and climatic factors in Queensland. CONCLUSIONS: These results suggest the potential for canine UCC incidence to be used as sentinel data in high-risk postcodes for human UCC.