Managing oral tumors (Proceedings)

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Managing oral tumors (Proceedings)

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Apr 01, 2009

Management of Oral Tumors

Oral tumors occur frequently in dogs and cats. Oral tumors account for approximately 6% of all malignant tumors in dogs with malignant cancer of the mouth and pharynx occurring 2.6 times more frequently in dogs than cats. Oral tumors can be benign or malignant. Unfortunately diagnosis of oral malignancies frequently occurs when the tumor is quite advanced necessitating more extensive treatment. Early diagnosis of oral tumors, appropriate staging, wide surgical resection and alternative treatment modalities can improve survival time.

Diagnosis of Oral Tumors

The diagnosis of oral tumors is based on biopsy of tissue followed by histopathologic examination. Small tumors or pedunculated lesions that can be resected with a gingivectomy may be primarily resected. Attempts to remove large oral masses with excisional biopsies are not recommended until a histopathologic diagnosis is available for surgical treatment planning.

Biopsy of large oral masses must be deep, because superficial biopsies may reveal only inflammation or gingival hyperplasia. A deep wedge biopsy or a deep Tru-cut is recommended. The use of electrosurgery for obtaining oral tumor biopsies is not recommended.

Clinical Staging of Oral Tumors

Following the histological diagnosis of oral malignancy clinical staging should include a complete blood count, serum biochemistry profile, urinalysis, fine needle aspirates of regional lymph nodes, and thoracic and skull radiographs. When available, advanced imaging techniques such as computed tomography and magnetic resonance imaging provide a more precise

An overview of feline oral squamous cell carcinoma (SCC) was recently published and included a review of the following: biologic behavior, pathology of SCC, diagnosis and staging, differential diagnosis, treatment options and prognosis.1 In summary this article reports that: oral SCC is a common malignancy in cats and responds poorly to treatment and that the mainstay of treatment is early diagnosis by use of oral examination, radiographic evaluation including advanced imaging techniques, biopsy and radical surgical excision.1 Recurrence despite aggressive surgical resection is common, thus multimodality therapy appears indicated.1 To date, cats that have been treated with mandibulectomy and curative-intent radiation post-operatively have had the longest survival times, however mandibulectomy has a high level of associated morbidity, but overall quality of life of the patients was felt to be good by most owners.

A wide variety of tongue lesions occur in dogs including: traumatic tongue lesions including severe multiple lacerations and tongue avulsions, foreign body granulomas, sublingual and buccal mucosal hyperplasia, lingual tumors, and glossitis secondary to chemical or immune-mediated diseases. A biopsy is often required to achieve a definitive diagnosis. Fine-needle aspirates and/or impression smears with cytologic evaluation along with gross evaluation of the lesion are often helpful in formulating a tentative plan. The most common malignant lingual tumor in dogs is the squamous cell carcinoma (SCC). Partial glossectomy is recommended for the treatment of lingual SCC in dogs when possible. In the past major resections of the tongue have not been commonly performed in animals because of concerns regarding unfavorable postoperative effects of diminished lingual function. A previous report in which major glossectomies were performed in five dogs demonstrated that glossectomies were well tolerated by dogs and that it may be a viable treatment option for aggressive tongue tumors and other conditions such as severe trauma or tongue avulsions that render the tongue unsalvageable. A classification system for glossectomies in humans have been applied for classification of major glossectomies in dogs. This classification system is divided into partial, subtotal, near total, and total glossectomies. A partial glossectomy is defined as excision or amputation of any portion or all of the oral (free) tongue rostral to the frenulum. A subtotal glossectomy involves the entire free tongue and a portion of the genioglossus, the geniohyoid muscles, or both, caudal to the frenulum. A near total glossectomy refers to resection of ≥ 75% of the entire tongue while amputation or excision of the entire tongue is defined as a total glossectomy. Two dogs in this study were successfully treated for total or complete avulsions of the tongue secondary to their tongues being entrapped in paper shredders with closure of the mucosa and placement of PEG tubes.