Oral tumors are common in both cats and dogs, accounting for 3-12% and 6% of all tumors in these species, respectively. In dogs, the most common malignant oral tumors are malignant melanoma, squamous cell carcinoma, and fibrosarcoma. Squamous cell carcinoma is the most common oral tumor in cats, followed by fibrosarcoma. For many patients, observation of a mass inside the mouth is the first indication for concern, although other symptoms may include increased salivation, facial swelling, bloody oral or nasal discharge, halitosis, weight loss, and/or difficulty eating.
Most oral tumors are locally invasive and may infiltrate rapidly into the surrounding normal structures, including the mandible and maxilla (lower and upper jaw bones). Malignant melanoma also has a very high risk for metastasis, with spread to other areas (usually the lymph nodes and/or lungs) noted in 50-80% of patients. Initial diagnostic steps for canine and feline oral tumors often include blood work, imaging (chest x-rays, abdominal ultrasound, and/or CT scan), and sampling (needle aspiration or biopsy). The results of these tests may then be used to guide treatment recommendations and prognosis.
When possible, surgical removal is typically recommended as the first component of the treatment process. Radiation therapy may be considered for incompletely excised tumors or for tumors that are not amenable to surgery. Chemotherapy may be considered for some aggressive tumor sub-types or for those with documented evidence of metastasis. A cancer vaccine (ONCEPT™) is available for patients with malignant melanoma. Prognosis for oral tumors is dependent on a number of factors and may range from a few months to over 2 years.
If your dog or cat is exhibiting symptoms that are suggestive of an oral tumor, evaluation by your primary care veterinarian is recommended. Once a diagnosis has been achieved, referral to our oncology department may be considered.