Oral Squamous Cell Carcinoma (Gingiva) in Dogs
What is Oral Squamous Cell Carcinoma?
Oral squamous cell carcinoma of the gingiva is locally invasive, but does not readily metastasize.
Diagnostic tests are recommended to determine which sites in the body are involved. These tests include:
- Complete blood count (CBC)
- Serum biochemistry panel
- Urinalysis (U/A)
- Regional lymph node evaluation
- Thoracic radiographs
Treatment ideally consists of complete surgical resection of the tumor. In the oral cavity, this often requires removal of a portion of underlying bone. Following surgery, outcome, function, and cosmesis are generally very good after an initial adjustment and healing period. If the tumor is too extensive for complete surgical excision, radiation therapy can be considered as an alternative treatment option - either to destroy residual microscopic disease or for macroscopic disease, bearing in mind that the efficacy is diminished when there is significant bulky disease. Radiation therapy consists of 19 treatments administered on a Mon-Fri schedule. Potential side effects of radiation include oral mucositis and moist desquamation that generally develops midway through treatment and lasts 2-4 weeks before resolving. During this time, patients are managed with anti-inflammatory analgesic medications as needed. There is also the potential, though unlikely, for late irreversible changes to underlying bone, muscle, nerve. Complete surgical excision with adequately wide margins suggests a very good long term prognosis. Reports on the use of radiation alone also describe the tumor to be radiation-responsive, with median disease control times of approximately 12-18 months. Several prognostic factors have been identified for canine oral squamous cell carcinoma including location (maxilla > mandibule; rostral > caudal) and tumor/radiation field size.
We also recommend piroxicam, an oral Non-Steroidal Anti-Inflammatory Drug (NSAID) which has anti-inflammatory and analgesic properties as well as possible anti-tumor activity against carcinomas. This medication should be given with food and the pet owner instructed to watch for signs of gastrointestinal upset (vomiting, change in stool, etc.). If such signs develop, piroxicam should be discontinued for 3-5 days. Restarting of therapy can then be considered in conjunction with the stomach-protectant misoprostil.
If definitive treatment is not an option, palliative radiation therapy can be considered. Palliative radiation therapy consists of two consecutive twice-daily doses of radiation therapy and is aimed at alleviating pain, inflammation, and swelling associated with the tumor. We recommend that the treatment be repeated in one month if no disease or symptom progression is noted in hopes of extending the duration of response.