Oral neoplasia in cats requires early detection and brisk therapy to provide any hope of a cure. Locally aggressive with the potential for distant metastasis, squamous cell carcinoma (SCC) is the No. 1 oral neoplasia in cats.1 Early gross changes may be minimal, and lesions often mimic other feline oral diseases such as tooth resorption and periodontal disease. Radiographic evaluation and examination of deep biopsy samples that include bone where available are critical diagnostic tools that differentiate this potentially fatal condition from other oral conditions.
Feline oral SCC carries a generally poor prognosis, with only 50 percent survival beyond one year after diagnosis.2 Therapeutically, radiation has proven less than ideal in cats with inoperable SCC,3 but a combination of radiation and chemotherapy is currently being evaluated as a possible option.4 There is evidence that 5-lipoxygenase inhibitors may also play a future role in therapy.5 Further studies in human head and neck SCC may provide clues to potential novel therapies in cats since similarities have identified cats as a potential model for human research.6-8 Recently two cats were treated favorably at the University of Missouri with strontium-90 (Sr-90) radiotherapy.9 But, to date, surgery has provided the most predictable mode of therapy.10
SCC involving the mandible may offer the best option for early surgical intervention, especially rostral and lateral lesions. Surgery is the treatment of choice for cure in select cases. The 3-cm margins achievable in dogs with malignant neoplasia are not feasible in cats with SCC because of small patient size. Margins, however, should be aggressive, and surgical therapy should be left to veterinary dental specialists. Cosmetics and function postoperatively can be very favorable (Figures 1-4).
Maxillary SCC is more challenging surgically because of the proximity of vital structures and the need for adequate margins into normal tissue. Gross lesions may appear as gingival inflammation and mimic periodontal disease (Figures 5 and 6). Often, extensive bone and soft tissue destruction is present at this time of diagnosis. In some cases of nonresectable SCC of the maxilla, I have performed debulking to eliminate the oral component of the disease (Figures 7 and 8). A common presentation is proliferation or ulceration adjacent to the maxillary arcade. If removal of painful exuberant oral tissue can result in adequate closure of the defect, patients respond quite favorably clinically. This removes the sensitive tissue from contact with food and normal tongue movements and, in some patients, can provide an excellent quality of life for months before local aggression again reaches a clinical level.
Sublingual SCC often leaves little hope for definitive surgical care. Presentation is generally proliferative or ulcerative (Figure 9). Although generally ineffective, debulking and closure can occasionally be effective at minimizing physical impingement of soft tissue, aiding in mastication and providing comfort. Multimodal pain management is a strong consideration in these patients. Short-term control is all that can be expected, and frequent quality-of-life evaluations should be performed.
Tonsillar SCC carries the poorest prognosis and the highest potential for distant and early metastasis. Therapy is palliative and consists of pain management and, again, frequent clinical assessments are necessary to ensure quality of life is maintained.