Canine Cancer: High Risk Breeds
Cancer is a common canine ailment. It is a killer in dogs, just as it is in humans. There are predisposing factors that have been identified such as exposure to substances like metals, dust, chemicals or pesticides. Diet plays a role in the development of cancer, as does exposure to UV light. Most dogs with cancer are middle-aged to older animals, but the effect of an animal’s age on cancer is not well understood. Cancer is found in all breeds of dogs even though some have a greater predilection. This article will concentrate on some of the common breeds and their predispositions to cancer.
In a 1997 Swedish study involving 222,000 dogs, the proportional mortality rate for cancer was 18.6 percent of the recorded deaths in 1993. These high-risk breeds (more than 10 percent dying of cancer) are: Boxer (36.9 percent), Giant Schnauzer (36.9 percent), Bernese Mountain Dog (32.7 percent), Irish Wolfhound (24.8 percent), Cocker Spaniel (22.2 percent), Doberman Pinscher (22.2 percent), Pomeranian (19.0 percent), Newfoundland (16.8 percent), German Shepherd Dog (14.8 percent), Saint Bernard (13.1 percent), Great Dane (12.3 percent), Greyhound (12.3 percent) and Basset Hound (percentage unknown, but the breed does have a genetic predisposition to lymphomas).
The most prevalent tumor location in dogs is the skin with 20 – 30% of these being malignant. Mast cell tumors, Histiocytomas, Squamous Cell Carcinomas and Melanomas are the most common.
Osteosarcoma is the most common primary bone tumor of dogs. Size rather than breed is considered more of a risk factor. However, there is a genetic predisposition in St. Bernards, Great Danes, Irish Setters, Dobermans, German Shepherds and Golden Retrievers.
Gender also plays a role. The most common tumor type in the female is a mammary gland tumor. In an intact male it would be the testicular tumor (neutering a male dog will eliminate the cancer risk). But there does not appear to be a breed predisposition to mammary gland tumors.
Lymphoma, a tumor arising from the hematopoietic tissue, is becoming more prevalent in certain breeds and at a younger age.
What follows is a partial list of some popular breeds and their predilections for cancer. It is interesting to note that there are some breeds with no predilection.
Airedale – Melanoma, Lymphosarcoma, Pancreatic carcinoma
Alaskan malamute – Sebaceous gland tumor, Anal sac adenocarcinoma
Australian Shepherd – None
Basset Hound – Mast cell tumor, Cutaneous haemangioma, Lymphosarcoma
Beagle – Mast cell tumor, Sebaceous gland tumor, Haemangiopericytoma, Perianal gland adenoma, Lymphosarcoma
Bichon Frise – Basal cell tumor
Border collie – None
Boston terrier – Mast cell tumor, Melanoma, Fibroma, Primary brain tumor
Boxer – Mast cell tumor, Melanoma, Cutaneous haemangioma, Histiocytoma, Sq. cell carcinoma, Fibroma, Thyroid neoplasia, Insulinoma, Osteosarcoma, Primary brain tumor, Lymphosarcoma.
Briard – None
Brittany spaniel – Liposarcoma (Lipoma)
Bull dog (English) – Mast cell tumor, Lymphosarcoma
Cavalier King Charles Spaniel – None
Chihuahua – Melanoma, Testicular neoplasia
Chow – Melanoma, Lymphosarcoma
Cocker Spaniel – Basal cell tumor, Sweat gland tumor, Trichoepithelioma, Cutaneous papilloma, Sebaceous gland tumor, Plasmacytoma, Histiocytoma, Fibrosarcoma, Perianal gland adenoma, Anal sac adenocarcinoma, Melanoma, Lipoma,
Collie – Sweat gland tumor, Histiocytoma, Haemangiopericytoma, Nasal cavity tumors, Colorectal neoplasia
Dachshund – Anal sac adenocarcinoma, Lipoma, Mast cell tumor, Sq.cell carcinoma, Histiocytoma, Ocular melanoma
Dalmatian – Actinic keratosis, Cutaneous haemangioma
Doberman – Melanoma, Lipoma, Histiocytoma, Fibroma, Myxoma, Primary brain tumor
Fox Terrier – Mast cell tumor, Fibroma, Haemangiopericytoma, Schwannoma, Insulinoma
German Shepherd – Sweat gland tumor, Trichoepithelioma, Anal sac adenocarcinoma, Cutaneous haemangioma, Lymphoma, Myxoma, Nasal cavity tumors, Colorectal neoplasia, Insulinoma, Limbal melanoma, Testicular neoplasia, Thymoma
Golden Retriever – Mast cell tumor, Sweat gland tumor, Trichoepithelioma, Melanoma, Haemangioma, Histiocytoma, Fibroma, Lymphosarcoma, Nasal cavity tumors, Thyroid neoplasia, Insulinoma, Primary brain tumor, Fibrosarcoma
Great Dane – Histiocytoma, Osteosarcoma
Greyhound – None..although beginning to see haemangiosarcoma
Havanese – None
Irish setter – Trichoepithelioma, Sebaceous gland tumor, Haemangiopericytoma, Lymphoma, Melanoma, Insulinoma
Jack Russell – Pituitary tumor
Labrador retriever – Mast cell tumor, Cutaneous histiocytoma, Sq. cell carcinoma, Nasal cavity tumors, Insulinoma, Lymphosarcoma, Limbal melanoma, Oral Fibrosarcoma, Thymoma
Lhasa Apso – Sebaceous gland tumor, Keratocanthoma, Perianal gland adenoma
Maltese – None
Miniature Pinscher – None
Pekingese – Sq. cell carcinoma
Pointers – Mast cell tumor, Haemangioma, Nasal cavity tumors
Poodle – Basal cell tumor, Trichoepithelioma, Sebaceous gland tumor, Sq. cell carcinoma, Insulinoma, Pituitary tumor, Adrenalcortical tumor, Lymphosarcoma, Limbal melanoma, Oral melanoma, Testicular neoplasia,
Pug – Oral melanoma, Mast cell tumor
Rottweiler – Sq. cell carcinoma, Histiocytoma, Osteosarcoma
Schnauzer – Trichoepithelioma, Sebaceous gland tumor, Melanoma, Lipoma, Histiocytoma, Sq. cell carcinoma, Testicular neoplasia, Limbal melanoma,
Scottish terrier – Mast cell tumor, Melanoma, Histiocytoma, Sq. cell carcinoma, Lymphoma, Primary brain tumor
Shar Pei – Histiocytoma, Mast cell tumor
Sheltie – Histiocytoma, Basal cell tumor, Lipoma, Nasal cavity tumors, Testicular neoplasia
Shih Tsu – Sebaceous gland tumor, Perianal gland adenomas
Siberian Husky – Basal cell tumor, Sebaceous gland tumor, Haemangiopericytoma, Perianal gland adenoma, Testicular neoplasia
Springer Spaniel – Trichoepithelioma, Histiocytoma, Melanoma, Anal sac adenocarcinoma,
Weimaraner – Mast cell tumor, Lipoma
Welsh Corgi – None
Westie – Histiocytoma
Yorkshire terrier – Keratocanthoma, Pituitary tumor, Testicular neoplasia
Cancer prevention is not well understood. In its simplest sense, cancer is a failure of the immune system to check uncontrolled growth of certain cells. As these cells multiply unchecked, they form tumors. If the tumors are unchecked, they metastasize. They send cancer cells all over the body to form more tumors.
There is ongoing research at several universities looking for better treatment options. Newer strategies include gene therapy, drugs that inhibit the metastasis process and chemotherapy-impregnated implants that release drugs in a slow, steady manner.