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Updated May 1, 2024 – As Morris Animal Foundation’s Golden Retriever Lifetime Study approaches its 13th year since its inception, it is no surprise that our team has begun to notice an uptick in cancer diagnoses among our Study cohort.  

We designed the Study to identify risk factors for cancer and other health problems. When we set out in 2012, we identified four cancers of particular interest. However, we carefully tracked all cancers in the cohort, and we added a fifth cancer to the list due to a higher-than-expected incidence.  

As we launch our annual Stop Cancer Furever campaign, it’s an excellent time to review the latest numbers from the Study, recap where we’re heading and discuss what this data means for dogs everywhere suffering from cancer.  

In brief, the five cancers of particular interest are: 


  • One of the most aggressive tumors of dogs  
  • Three common sites: spleen, right atrium of the heart and skin  
  • Multiple breeds have a higher incidence, but any dog can be affected  
  • It affects older dogs (average age 10 years) more frequently than young dogs 
  • 90% of dogs die within one year of diagnosis, even with treatment  
  • Cause of 70% of cancer deaths in the Golden Retriever Lifetime Study cohort  
  • As of March 1, 2024, 407 dogs in the Study have been diagnosed with hemangiosarcoma  

To learn more about hemangiosarcoma, check out our hemangiosarcoma resources page.  


  • Most common type of cancer diagnosed in dogs  
  • Similarities to non-Hodgkin’s lymphoma in people  
  • Although several breeds are predisposed to lymphoma, any dog can be affected.  
  • Many different subtypes are now recognized, which affect prognosis and treatment.   
  • As of March 1, 2024, 179 dogs in the Study have been diagnosed with lymphoma.  


  • The most common primary bone tumor in dogs  
  • Large and giant-breed dogs are predisposed   
  • Height is a more significant risk factor than breed  
  • It occurs most commonly in dogs 7-9 years of age and 1-2 years of age  
  • As of March 1, 2024, 21 dogs in the Study have been diagnosed with osteosarcoma 

Mast Cell Tumor

  • The most common malignant skin tumor in dogs  
  • Many breeds are at risk; the highest incidence is in brachycephalic breeds (shorter-nosed and flat-faced dogs)  
  • Experts divide mast cell tumors by grade based on microscopic appearance – the higher the grade, the worse the prognosis.  
  • Lower-grade tumors are curable. 
  • Surgery is the first and best treatment choice.  
  • As of March 1, 2024, 36 dogs in the Study have been diagnosed with high-grade mast cell tumors and 146 with lower-grade mast cell tumors.  

Histiocytic Sarcoma  

  • Most common in middle-aged and older dogs  
  • Breeds at risk include Bernese mountain dogs, golden retrievers, flat-coated retrievers, Rottweilers, miniature schnauzers, and Pembroke Welsh corgis.  
  • One of the deadliest cancers affecting dogs   
  • As of March 1, 2024, 46 dogs in the Study have been diagnosed with histiocytic sarcoma. 

The Golden Retriever Lifetime Study is a rare opportunity for researchers to find answers to some of the deadliest cancers affecting dogs.   

Only 1,424 of the original 3,044 dogs remain. Some dogs have withdrawn, some dogs are inactive, but cancer has claimed the lives of 1,132 dogs, with an astounding 75% of these deaths attributed to it. Thanks to the tireless efforts of our owner participants, we’ve collected extra data and biologic samples on the dogs diagnosed with cancer, providing our researchers with a unique opportunity to study cancer in previously impossible ways.   

Science to Save Animals 

The sad truth is that despite intense research, we still have a long way to go to improve the quality of life and longevity of dogs suffering from cancer. That’s why we started the Stop Cancer Furever campaign nearly 10 years ago and launched our Hemangiosarcoma Initiative in 2022. We know that investing in science can save the lives of the thousands of precious animals afflicted with cancer each year.   

We need your help to make the future brighter for all the dogs that make our lives better. 

During our Stop Cancer Forever campaign, which runs from May 1 through June 30, all donations received will help fund animal cancer research. Our friends at Petco Love and Blue Buffalo share our vision of a cancer-free future for the animals we love. Donate today and they’ll match your gift dollar for dollar, up to $100,000, through June 30, 2024. 

Together, let's Stop Cancer Furever!

Additional Resources  


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No Pet Should Have to Suffer From Cancer

You can help Stop Cancer Forever with your donation today. Now through June 30, all gifts will be matched, up to $100,000.