What causes cancer in dogs and cats?

We know the cause of very few cancers in companion animals. The development of cancer can occur in any organism from excessive exposure to carcinogenic agents such as certain chemicals, UV or X-irradiation and from some viral infections (such as feline leukemia).

Although we do not know the exact cause for each type of cancer in pets, the underlying problem is due to abnormal genes that result in uncontrolled growth of cells which may invade into surrounding tissues or spread to other areas. The number of cancers that are actually heritable (capable of being passed on to offspring) is unknown in dogs and cats, but it has been occasionally documented.

What are the warning signs of cancer?

• Abnormal swellings that persist or continue to grow
• Sores that do not heal
• Weight loss
• Loss of appetitie
• Bleeding or discharge from any body opening
• Offensive odor
• Difficulty eating or swallowing
• Hesitation to exercise or loss of stamina
• Persistent lameness or stiffness
• Difficulty breathing, urinating or defecating

What is the cost of cancer treatment?

The cost of evaluation, diagnosis, staging and treatment will vary depending on the site of the tumor, the size of the dog, the type of treatment selected and how well your pet handles the treatment. In general, the initial evaluation, including the diagnosis, staging and a discussion about the prognosis and treatment options may range from several hundred dollars upward if the tumor is located in a body cavity or hard to reach location.

Major surgical procedures will likely range from about $500 upward, depending on the extent of surgery and the recovery period. Chemotherapy costs vary with size of the dog but for many treatment regimens the cost of chemotherapy may range from several hundred dollars for palliative oral treatment to several thousand dollars over a three-to-six-month period. Radiation therapy will range from approximately $2500-$7000. There are additional fees if a CT scan is required for treatment planning or if the patient needs additional monitoring in our intensive care unit.

What are the side effects of chemotherapy in pets?

The goal of chemotherapy in pets with cancer is to preserve the highest quality of life possible. However, there may be some side effects following treatment with chemotherapy. The overall impact of side effects is reduced by altering doses or eliminating drugs from treatment if side effects are significant. However, in order to obtain any benefit from chemotherapy, it is necessary to use doses that can result in some reversible and temporary effects on normal tissues.

The most common side effects of chemotherapy in pets include: Stomach upset resulting in a reduced appetite, nausea, vomiting, diarrhea and dehydration. These effects are generally mild and self-limiting but may require symptomatic treatment or hospitalization in some instances.