Veterinary Medicine - June 2007 - (Page 392)
CE O PEER-REVIEWED Feline oral squamous cell carcinoma: An overview These fast-growing, painful tumors are not uncommon in cats, and few affected patients survive long-term. But a patient’s chances can improve if you identify and address the disease early. Jennifer J. Marretta, DVM Laura D. Garrett, DVM, DACVIM (oncology) Sandra Manfra Marretta, DVM, DACVS, DAVDC T he oral cavity is a common site for neoplasia in cats, accounting for about 10% of all feline tumors. 1 The most common malignant oral tumor in cats is squamous cell carcinoma.1 The prognosis for this fast-growing, invasive tumor is grave, so it is vital to identify and treat it early. To help you manage affected patients, this article focuses on the biologic behavior, pathology, etiology, diagnosis, staging, and treatment of feline oral squamous cell carcinoma. BIOLOGIC BEHAVIOR Oral squamous cell carcinoma is a malignant tumor that may occur anywhere within the oral cavity, is locally invasive, infrequently metastasizes to ipsilateral regional lymph nodes, and rarely spreads to distant sites.1,2 The most common site of oral squamous cell carcinoma in cats is the sublingual region (Figure 1). The maxillary and Jennifer J. Marretta, DVM Laura D. Garrett, DVM, DACVIM (oncology) mandibular gingivae are also sites of primary tumor development. Infrequently, squamous cell carcinoma may arise from the tonsillar epithelium. Mucosal ulceration, necrosis, and severe suppurative inflammation are commonly associated with oral squamous cell carcinoma (Figure 2). Gross tumor proliferation is often evident in the oral cavity. However, the mucosa can also remain intact over a raised region caused by squamous cell carcinoma invading into deeper tissues (Figure 3). Cats may present for evaluation of an enlarged jaw, as the tumor can make the mandible look prominent or asymmetrical (Figure 4). Gingival squamous cell carcinoma often invades the underlying mandible or maxilla, leading to severe and extensive tumor involvement of the bone in that area. Local disease is usually the cause of death. PATHOLOGY Oral squamous cell carcinomas grow rapidly. On initial presentation, the tumor is often extremely advanced, resulting in a grave prognosis. The metastatic rate at diagnosis is low, yet the true metastatic potential is unclear because so few cats have their local disease controlled to permit long-term follow-up for metastatic disease.2 In four studies comprising 81 cats with oral squamous cell carcinoma, 12 cats (14.8%) had documented metastasis to the ipsilateral submandibular lymph node. 3-6 The actual rate of metastasis may have been somewhat higher, as not all cases had cytologic or histologic lymph node evaluation. In eight cats (10%), metastasis was diagnosed at presentation,3-5 while four cats (5%) developed lymph node metastasis after primary tumor treatment.6 Of these four cats, one was euthanized because of the metastasis; the other three were euthanized because of local tumor progression.6 Thoracic radiographs were evaluated in three of the studies, comprising 74 cats, and no evidence of thoracic metastasis was present at initial presentation in any patient.3,5,6 In one cat that had lymph node metastasis, follow-up thoracic radiographs 16 months after treatment showed no evidence of pulmonary metastatic spread.4 These findings are consistent with the belief that feline maxillofacial squamous cell carcinomas have a low metastatic rate and that local disease is usually the cause of death. Sandra Manfra Marretta, DVM, DACVS, DAVDC ETIOLOGY AND RISK FACTORS The average age of cats with oral squamous cell carcinoma is 12.5 years, with a range of 3 to 21 years. No significant sex or breed predilection is associated with this tumor. Although several en- Department of Veterinary Clinical Medicine College of Veterinary Medicine University of Illinois Urbana, IL 61802 392 June 2007 Veterinary Medicine
Table of Contents for the Digital Edition of Veterinary Medicine - June 2007
In Memoriam: Dr. James R. Richards
A Veterinary Medicine Interview: Dr. David S. Bruyette
What’s New in Dermatologic Therapy?
Feline Oral Squamous Cell Carcinoma: An Overview
Mind Over Miller
Special Supplement: Heartworm-Associated Respiratory Disease in Cats
Veterinary Medicine - June 2007
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