Common Cancer in Pets

Explore the most common cancers that harm our beloved pets. Learn about the many types, where they can be found, the prognosis, and treatment choices.

Dog sitting on the floor
Cat sitting on a window sill
Mobile Cancer Care

The Most Common Pet Cancers We See

One of the most common questions I get when people hear I’m an oncologist for pets is, “What type of cancer do pets get?”

In general, pets can get the same types of cancer that humans also develop. The frequency of given types differs, but the overall conditions are the same.

The most common cancers we treat here at Private Veterinary Specialties are:

Dogs: Lymphoma, mast cell tumors, bone cancer (osteosarcoma), Hemangiosarcoma, and transitional cell carcinoma of the bladder.

Cats: Lymphoma ( large and small cell) as well as injection site sarcomas.

Each of these cancers is treated differently with different prognosis. Below is an introduction to each cancer. Please note this information is an introduction and does not replace an in-person oncology consultation.

Canine Lymphoma (Dogs)

What is it?
This is a cancer of the immune system or white blood cells called lymphocytes. These cells tend to divide rapidly, so this cancer is noted to come on quickly.
How bad is it?
Canine lymphoma comes on quickly but also responds quickly to treatment. Dog lymphoma tends to be rewarding to treat as most dogs respond well to chemotherapy and can enjoy a prolonged quality of life. General survival times are 6-12 months, depending on various factors.
Where is it?

Most commonly, lymphoma in dogs is found in the peripheral lymph nodes. Other locations for lymphoma can be the spleen, liver, intestines, and skin. Other locations are also possible but much less common.

How is it treated?
Chemotherapy and steroids tend to be the core therapy for treating lymphoma in dogs. Other therapies are on the horizon, such as immunotherapy; however, they are not yet mainstream. Many chemotherapy protocols exist, allowing pet owners with various schedules and situations to treat their dogs. The most commonly utilized protocol is a CHOP-based chemotherapy protocol, as they have been proven over the years to be effective and well tolerated. The newest canine lymphoma treatment is a drug called Tanovea. Tanovea is the first new drug for canine lymphoma in 20+ years. This drug is given once every three weeks for five treatments, so it is both a new and a convenient treatment option. For more information on Tanovea, you can visit VetDC. It is important to note all of these chemotherapy treatments are palliative in that they extend and maintain quality of life but rarely cure dogs of lymphoma.

Canine Mast Cell Tumor (Dogs)

What is it?
This cancer is of cells that are part of the immune system and most commonly become reactive during allergic reactions. Mast cells release histamine and heparin, which make you red and puffy during an allergic reaction. In dogs, mast cell tumors cause major GI upset such as vomiting, diarrhea, lack of appetite, stomach ulcers, low blood pressure, skin redness, and edema. These signs can start as non-specific in some patients but are tied to the tumors once they are identified.
How bad is it?
Mast cell tumors are noted to vary from benign to malignant based on biopsy results. Biopsy is essential to help understand how a given mast cell tumor will behave.
Where is it?
Mast cell tumors in dogs are most commonly noted on the skin. Mast cell tumors are one of the most common skin tumors in dogs. Unlike other skin tumors, these tumors can be noted to “develop overnight”; this is because they can become swollen. In some cases, they can develop in internal organs, going undetected until dogs show signs of GI upset or low blood pressure.
How is it treated?
Canine mast cell tumors are treated in a variety of ways. In general, solitary tumors are treated with surgery to remove them. Based on the biopsy obtained from surgery, we determine if additional therapy is needed, such as chemotherapy.

Canine Bone Cancer (Osteosarcoma)

What is it?

Osteosarcoma (OSA) is bone cancer in dogs that arises from the bone itself, most commonly in large to giant breed dogs.

How bad is it?

Osteosarcoma is a painful cancer that typically needs aggressive therapy to both control the bone pain and spread of the cancer. Survival times for this cancer range from 9-15 months when treated with amputation and chemotherapy.

Where is it?
Osteosarcoma is a cancer that starts in the bone, most commonly in leg bones. Over time, this cancer is commonly spread to the lungs and, in some instances, other organs.
How is it treated?
Multiple treatment options exist which can be customized based on what the patient needs and the owner’s wishes. The most common treatment for this disease is amputation of the leg, followed by IV chemotherapy. Newer treatments, such as immunotherapy and small molecular inhibitor drugs, are also starting to become available. Two companies offering immunotherapy for OSA are Aratana and Elias. Both products aim to harness the immune system to attack the cancer after surgery and chemotherapy are completed. Immunotherapy with their products is showing promise in extending survival times.