Cancer in Dogs

How Common is Cancer?
Cancer is common in pet animals, and the rate increases with age. Dogs get cancer at roughly the same rate as humans, while cats get fewer cancers. Cancer accounts for almost half of the deaths of pets over 10 years of age.
How is it Diagnosed?
Strong circumstantial evidence of cancer can be attained from x-rays, blood tests, the physical appearance of the cancer, or the physical signs caused by the cancer. Most cancers, however, will require a biopsy (removal of a piece of tissue) for confirmation.
Is Cancer Preventable?
Some cancer, such as breast cancer, is largely preventable with early spaying. Unfortunately, the cause of most cancers is not known and therefore prevention is difficult.
Common Signs of Cancer in Pets
Abnormal swellings that persist or continue to grow
Sores that do not heal
Weight loss
Loss of appetite
Bleeding or discharge from any body opening
Offensive odor
Difficulty eating or swallowing
Hesitance to exercise or loss of stamina
Persistent lameness or stiffness
Difficulty breathing, urinating, or defecating
Many of the above signs are also seen with noncancerous conditions but still warrant prompt attention by your veterinarian to determine the cause. Cancer is frequently treatable, and early diagnosis will aid your veterinarian in delivering the best care possible.
Common Types of Cancer in Pets
Skin - Skin tumors are very common in older dogs, but much less common in cats. Most skin tumors in cats are malignant, but in dogs they are often benign. All skin tumors should be examined by your veterinarian.
Breast - Fifty percent of all breast tumors in dogs and 85% of all breast tumors in cats are malignant. Spaying your pet between 6 and 12 months of age will greatly reduce the risk of breast cancer. Surgery is the treatment of choice for this type of cancer.
Head & Neck - Cancer of the mouth is common in dogs and less common in cats. A mass on the gums, bleeding, odor, or difficult eating are signs to watch for. Many swellings are malignant, so early aggressive treatment is essential. Cancer may develop inside the nose of both cats and dogs. Bleeding from the nose, difficulty breathing, or facial swelling may occur.
Lymphoma - Lymphoma is a common form of cancer in dogs and cats. It is characterized by enlargement of one or many lymph nodes in the body. A virus causes most of these cancers in cats. Chemotherapy is frequently effective in controlling this type of cancer.
Feline Leukemia Complex - The feline leukemia virus is contagious among cats and will occasionally cause true cancer. There is no proof that it is contagious to humans. While a great deal of research is ongoing, no consistently effective treatment is presently available for virus-positive cats.
Testicles - Testicular tumors are rare in cats and common in dogs, especially those with retained testes. Most of these cancers are curable with surgery.
Abdominal Tumors - Tumors inside the abdomen are common. It is difficult to make an early diagnosis. Weight loss and abdominal enlargement are common signs of these tumors.
Bone - Bone tumors are most commonly seen in large breed dogs and rarely in cats. The leg bones, near joints, are the most common sites. Persistent lameness and swelling of the leg is an early sign of disease.
How is it Treated?
Each cancer requires individual care. Your veterinarian may use surgery, chemotherapy, radiation, cryosurgery (freezing), hyperthermia (heating) or immunotherapy to effectively treat cancers. Combination therapy is commonly employed.
What is the Success Rate?
This depends strongly on the type and extent of the cancer as well as the aggressiveness of therapy. Some cancers can be cured, and almost all patients can be helped to some degree. Your veterinarian will have a better chance to control or cure your pet's cancer if it is detected early.