Contact with dogs is associated with improved survival in cancer patients.

For cardiovascular diseases, diabetes, and asthma, the positive effects of dog ownership are shown. Cancer is a leading cause of death, but the influence of dogs on cancer incidence and survival is not well examined. As modifiable lifestyle factors gain importance in cancer survivorship research, the potential protective role of dog ownership warrants systematic investigation. We retrospectively analyzed clinical data from a federated global health research network, focusing on patients diagnosed with cancer (International Classification of Diseases (ICD-10): C00-D49). From these, we generated two cohorts with contact with dogs (cohort 1) and one without (cohort 2). After propensity score matching for age and sex, a total of about 55,000 patients were included. Analysis of the matched cohort demonstrated that dog ownership was significantly associated with reduced 5-year all-cause mortality in cancer patients compared to non-owners (RR = 0.44). Survival analysis revealed a significantly higher 5-year cumulative survival rate among dog-owning patients versus non-owners, with a hazard ratio (HR) of 0.36. Contact with dogs is associated with a 64% relative risk reduction in cancer mortality, potentially mediated by increased physical activity, psychosocial support, and microbiome modulation. While retrospective design precludes causal inference, this first large-scale matched cohort study provides compelling epidemiological evidence warranting prospective validation.