Dog Breeds and Cancer: Which Dogs Have Increased Risk?
According to the Veterinary Cancer Society, 1 in 4 dogs will develop malignant cancer in their lifetime—and for those 10 years old and older, that statistic rises to 1 in 2. With 6 million new cases of dog cancer diagnosed each year in the U.S., this disease has become the leading cause of death in adult dogs.
Despite ever-increasing research into varied cancer treatments, the lack of reasonable early detection strategies means that treatments are often aimed at late-stage, unresponsive, or relapsing disease. However, research shows that many canine cancers likely have latency periods of up to several years, so the right screening tools could help veterinarians diagnose cancer before clinical signs appear and greatly increase the chances for treatment success. Additionally, knowing the common types of dog cancer and the breeds frequently affected can allow you to get a jump on cancer diagnoses sooner rather than later, leading to a better survival rate.
Dog Breeds and Common Cancer Types
The first step on the road to better cancer diagnostics is recognizing which dogs have a higher risk of developing cancer and which dog cancer types you need to watch for based on patient signalment. One study found that although most dogs have a similar lifetime risk, purebred dogs and large breeds developed cancer at younger ages than mixed-breed or smaller dogs. Screening these dogs at younger ages can result in earlier cancer detection and improved case outcomes.
The Veterinary Cancer Society lists the most common dog cancers as lymphoma, osteosarcoma, mast cell tumor, hemangiosarcoma, melanoma, and transitional cell carcinoma. Mammary tumors, soft tissue sarcomas, and lung cancers are also common. Several breeds have well-known predispositions for certain cancer types that are less common in the general dog population, such as transitional cell carcinoma in Scottish and West Highland terriers, and histiocytic sarcoma in Bernese mountain dogs. Beyond this, many veterinarians are unfamiliar with dog breed cancer predilections.
In a recent mortality study in the U.K., 27% of purebred dogs on average suffered from a cancer-related death. Additionally, the top five breeds most likely to develop cancer, nearly 50% died of cancer. These breeds included the Irish water spaniel, flat-coated retriever, Hungarian wirehaired vizsla, Bernese Mountain dog, and rottweiler.
A few breeds—most famously, the golden retriever—are overrepresented in other cancer studies. In the referenced study, many global breeds outranked the golden retriever, whose cancer mortality rate was 38.8%. Popular U.S. breeds with a higher mortality rate due to cancer include Bernese Mountain dog and Rottweiler. Other notable mentions include the boxer, briard, French bulldog, and bullmastiff.
Breed-cancer predisposition may relate to the ancestral origin because spitz-type breeds tend to develop cancer less often than mastiff types, and other groupings from Asia, Africa, and Europe cluster together on the risk tables.
Breed Influence on Cancer
Specific cancers afflict certain breeds more frequently than others, regardless of the breed's overall cancer risk. The most common cancer types and breeds most commonly affected are as follows:
Histiocytic sarcoma: This is common in Bernese mountain dogs and flat-coated retrievers as well as golden retrievers and rottweilers.
Osteosarcoma: This mostly affects large and giant breeds, including rottweilers, great Danes, Irish wolfhounds, Scottish deerhounds, borzois, greyhounds, Saint Bernards, Dobermans, German shepherds, golden retrievers, and Leonbergers.
Hemangiosarcoma: German shepherds, boxers, and golden retrievers are often affected by hemangiosarcoma.
Mast cell tumor: This is common in boxers and bully breeds, including the bullmastiff, Boston terrier, and Staffordshire bull terrier, as well as the pug, Rhodesian ridgeback, Weimaraner, beagle, shar-pei, and Labrador and golden retrievers.
Lymphoma: Boxers, bulldogs, bullmastiffs, English springer spaniels, Labrador and golden retrievers, rottweilers, basset hounds, Saint Bernards, Scottish terriers, Airedale terriers, and Bouvier des Flandres all have a predisposition to lymphoma.
Melanoma: Melanoma commonly affects schnauzers, Scottish terriers, poodles, cocker spaniels, chow chows, golden retrievers, and Pekingese.
Mammary tumors: These mostly affect intact female dogs or female dogs not spayed until after 2 years old. Overrepresented breeds with mammary tumors include boxers, spaniels, small terriers, dachshunds, setters, pointers, and German shepherds.
New Dog Cancer Screening Protocols
By identifying the highest-risk breeds, veterinary professionals can employ more effective screening strategies. Traditional blood cancer screenings have previously been cost-prohibitive, preventing serial screenings that increase accuracy, and require large blood samples that can be difficult to obtain from small or wiggly dogs.
Newer, more affordable testing—with quick turnaround times and requiring a routine blood sample—can easily be integrated into your preventive care offerings. This cutting edge test detects circulating nucleosomes which are often elevated in seven common canine cancers. A finding of increased circulating nucleosomes identifies dogs who likely have cancer and can prompt you to discuss further diagnostics with clients to locate, identify, and stage the cancer.
The average age of cancer onset in dogs is around 8 years old, so canine cancer screening is recommended annually for all dogs 7 years or older. Purebred dogs, large breeds, and other high-risk breeds that develop cancer at younger ages should be screened beginning at age 4. By adding cancer screening to your preventive care protocols, you can take the first step towards earlier cancer diagnosis before the dog experiences clinical signs and more affordable, effective treatment options may still be possible..