Haemangiosarcoma in the Golden Retriever Lifetime Study: frequency, risk factors and post-diagnosis survival

Background The Golden Retriever Lifetime Study (GRLS) is a prospective, longitudinal cohort study launched in the United States in 2012 to investigate genetic, environmental, and lifestyle factors contributing to disease. As the cohort of dogs now approaches end of life, it presents unique opportunities to explore haemangiosarcoma—a highly aggressive malignancy commonly reported in Golden Retrievers and the most commonly diagnosed tumour in the GRLS cohort. This study aimed to calculate incidence, explore potential risk factors for diagnosis, and describe tumour-specific survival. Methods Dogs diagnosed with haemangiosarcoma before December 31st, 2024, were classified as cases and all remaining dogs as non-cases. Data from owner and veterinarian surveys, along with necropsy reports, were processed to derive variables on demographics, lifestyle, environmental exposures, comorbidities, and medications. Analyses of the non-demographic, potentially modifiable factors were considered exploratory given the limited prior evidence and potential for residual confounding. Risk factor analysis for haemangiosarcoma diagnosis used multivariable binary logistic regression modelling. Median survival times (MST) were calculated. Results Overall, 490 of 3,044 dogs (16.1%) were diagnosed with haemangiosarcoma, giving an incidence rate of 1.69 (95% CI: 1.54–1.85) cases per 100 dog-years. Dogs aged < 7 or ≥ 10 years had lower odds of diagnosis than those aged 7–9 years. Male sex, higher median adult bodyweight, gastrointestinal comorbidities and NSAID use were associated to higher odds of diagnosis, Previous cancer history and higher owner-reported activity levels were associated with reduced odds of diagnosis. MST from diagnosis across all body-locations was 0 days (95% CI: 0–0), but cutaneous haemangiosarcoma showed a significantly longer median survival (log-rank test p < 0.01) of 19 days (95% CI: 0–479). Conclusions This study provides a longitudinal epidemiological profile of haemangiosarcoma in Golden Retrievers. The relatively high incidence rate and poor outcomes observed highlight the ongoing clinical challenges of this disease. Risk factor modelling identified both established (age, sex, bodyweight) and novel associations (NSAID use, gastrointestinal comorbidities, prior cancer, activity level). While these novel associations are hypothesis-generating and warrant cautious interpretation, they provide direction for future research to validate findings and elucidate underlying mechanisms.