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 Cancer – Locally Invasive
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
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.
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