6. Great Dane

Known for their hunting skills, large size, and graceful appearance, Great Danes make well-mannered family companions. Unfortunately, they are among the dog breeds with higher rates of cancer.

With an average lifespan between seven and 10 years, Great Danes are more at risk of developing osteosarcoma than most other giant dog breeds. Osteosarcoma, also known as bone cancer, is a very aggressive form of cancer that cannot be cured. Early symptoms include leg pain and lameness.

Great Danes are also at risk of hemangiosarcoma and lymphoma. Fortunately, lymphoma is one of the few forms of cancer that can often be discovered with a blood test. This being said, experts recommend complete blood testing twice a year.