Canine Mouth Cancer: Malignant Oral Tumors & Treatment Options

Canine malignant mouth cancer can be divided into:
- locally invasive
- metastatic (spread to other parts of the body)

Locally invasive malignant mouth tumors are fibrosarcoma and squamous cell carcinoma.

Metastatic malignant mouth tumors are melanoma and osteosarcoma.

Canine Mouth CancerLocally Invasive

1. Fibrosarcoma

Fibrosarcoma often develops on the gums. Although locally invasive (bone invasion), it may spread to the lungs. Oral fibrosarcoma is treated with surgery and/or radiation therapy. The recurrence rate is about 40-65% after surgery.

2. Squamous Cell Carcinoma

Although this tumor usually affects the gum, it can also form on the tongue and tonsils.

Squamous cell carcinoma of the tongue:
- usually invades the bone
- about 5-10% metastatic rate
- often recur following treatment

Squamous cell carcinoma of the tongue and tonsils:
- tend to spread to local lymph nodes and lungs
- high recurrence rate

Oral squamous cell carcinoma is treated with surgery, radiation therapy and/or chemotherapy. Tumors located in the front part of the jaw are easier to treat and have better prognosis.

Canine Mouth Cancer – Metastatic

1. Melanoma

Melanoma is the most common canine mouth cancer. It usually occurs in dogs with dark pigmented oral mucosa and located on the gum. Melanoma is highly metastatic. By the time it is diagnosed, the tumor is likely to have spread to local lymph nodes or lungs.

The conventional canine melanoma treatment is surgery and/or radiation. In January 2010, canine melanoma vaccine ONCEPT gained full approval from USDA for treatment of oral melanoma in dogs. This therapeutic vaccine is used in combination with surgery and/or radiation therapy.

2. Osteosarcoma

Osteosarcoma is a malignant bone cancer.

Tumor located in the upper jaw: highly metastatic, prognosis is poor.
Tumor is located in the lower jaw: lower risk of spread, so prognosis is generally better.

Treatment for oral osteosarcoma is surgery and/or chemotherapy

See also: Mouth Cancer in Dogs Symptoms – What to Look Out for
See also: Mouth Cancer in Dogs – Treatment Options

Secondhand smoke causes cancer in dogs and cats

Secondhand smoke has been known to adversely affect non smoking people. Are you aware that pets are also seriously affected? Several studies have shown that secondhand tobacco smoke causes certain types of cancer in dogs and cats.

Colorado State Univ conducted 2 studies to determine whether exposure to environmental tobacco smoke increases the risk of nasal and lung cancer in dogs.

They discovered that:
- long-nosed dogs such as pugs and pit bulls, have an increased risk of nasal cancer. This could be due to enhanced filtration and exposure of nasal membrane to carcinogens.
- short-nosed dogs such as collies and German Shepherds, have an increased risk of lung cancer. A possible explanation could be that the lungs are exposed to more carcinogens as less are being filtered in the nose.

Dog lung cancer, nasal cancer dogs

In a study conducted by Tufts University School of Veterinary Medicine and the University of Massachusetts, cats exposed to environmental tobacco smoke have a higher risk of developing feline lymphoma.

In another study, also by Tufts University School of Veterinary Medicine and the University of Massachusetts, cats develop feline oral squamous cell carcinomas (SCC) from exposure to environmental tobacco smoke. Cats living in a smoking household are exposed to carcinogens through inhalation and ingestion. As cats tend to lick themselves during grooming, they also ingest other types of chemicals from anti flea products. Cotinine (metabolized nicotine) has been detected in the urine of cats exposed to passive smoking.

Quit smoking

If you smoke and own a pet, quit the habit. Don’t risk the lives of your pet and other non smokers (kid, wife, husband, mum, dad, etc) in the same household. Watch out for respiratory problems in your pet as these can be signs of lung or nasal cancer.