+ 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

ORAL SQUAMOUS CELL CARCINOMA