+ Biologic Behavior
- SCC accounts for 75% of oral tumors in cats and is the most common feline oral tumor
- Flea collars, high canned food, canned tuna fish ± cigarette smoke significantly increase the risk of oral SCC
- Median age 12 years (range, 2.5-18.0 years)
- No sex predilection
- Site predilection: tongue, pharynx, or tonsils (42%), mandible (27%), and maxilla (27%)
- Bone involvement is common and extensive
- Perineural infiltration by mandibular SCC may be responsible for tumor extension into the retrobulbar space
- Regional lymph node and distant metastasis is rare
- However, local tumor control is often poor and long-term course is unknown
- Paraneoplastic hypercalcemia has been reported
TREATMENT
+ Surgery
Surgical techniques: mandibulectomy and maxillectomy
+ Radiation Therapy
- Improves survival rate when combined with either surgery or chemotherapy
- Radiation therapy with 6 weekly fractions of 6 Gy and twice weekly low-dose gemcitabine (25 mg/m 2) as a radiation sensitizer results in an overall response rate of 75%, median duration of response of 42.5 days, and a MST 111.5 days
- Palliative radiation therapy is not effective with radiation-induced complications or PD in 86% (6/7) cats
+ Chemotherapy
- No known effective chemotherapeutic agent for primary or metastatic SCC
- Mitoxantrone, carboplatin (which has shown in vitro activity against feline SCC), and combination of doxorubicin and cyclophosphamide have been used either alone or in combination with radiation therapy with some effects
- Liposome-encapsulated cisplatin is ineffective and causes acute toxic reactions
+ Prognosis
- Prognosis is poor with 12-month survival rate usually < 10%
- MST 45 days with surgery alone
- MST 90 days with radiation therapy alone
- MST 14 months with hemimandibulectomy and radiation therapy
- MST 75-170 days with radiation therapy and chemotherapy (cisplatin, carboplatin, gemcitabine, or mitoxantrone)
- MST 75 days with radiation therapy and local hyperthermia