"Squamous Cell Carcinoma of the Gingiva" TUMOR TIDBITS, A BIWEEKLY VETERINARY ONCOLOGY E-LETTER Volume 3; Number 2; January 16, 2002. Editor: Kevin A. Hahn, DVM, PhD, Dipl - ACVIM (Oncology) & Overall Nice Guy! ANNOUNCEMENTS * Free chemotherapy for dogs with lymphoma! Yes - FREE. Beginning April 15th we begin a clinical trial for dogs with lymphoma. We're only one of three clinics in the nation participating in a trial to help dogs with lymphoma. All costs for patient evaluation and treatment are at NO CHARGE to the pet owner! Call or email us for additional details. * Celebrate LIFE with us at Gulf Coast Veterinary Oncology. Saturday March 23rd from 2-5 pm at Gulf Coast we are dedicating a display case to Celebrate Life. Bring your favorite memento or picture (sorry no pets allowed for the celebration) and we'll include it in our display. For additional details, as for Dr. Freeman or any of our staff. * We're proud of our Oncology Nurses. Have a question? Ask to speak to Aimee, Amy, Sherry, Lloyd or Trish! They provide the finest care anywhere! THIS WEEK'S TUMOR TIDBIT: SQUAMOUS CELL CARCINOMA OF THE GINGIVA HERE'S AN OVERVIEW OF WHAT'S IN THE TEXTBOOKS: * Squamous cell carcinoma of the gingiva causes progressive, rapid (weeks) local invasion of neoplastic epithelial cells within in the oral cavity in dogs and cats. It is the most common oral malignancy in cats and second most common in dogs. The squamous cell carcinoma is highly invasive to bone with a nonencapsulated, raised, irregular, ulcerated, or necrotic surface. Metastasis is rare, with spread to lymph nodes more common than the lungs. Cause of death is secondary to local recurrence and cachexia. SIGNALMENT * Mean age of dogs and cats is 10.5 years (range, 3 to 15 years). There is no sex or breed predilection. It is more common in medium- and large-breeds dogs than small dogs. The most common site is the rostral mandible. SIGNS Historical Findings * Excessive salivation * Dysphagia * Halitosis * Weight loss Physical Examination Findings * Loose teeth * Bloody oral discharge * Facial deformity * Cervical lymphadenopathy in a few patients * Reactive hyperplasia (> 50%); metastatic tumor (< 50%) DIFFERENTIAL DIAGNOSES * Amelanotic melanoma * Fibrosarcoma * Epulis * Abscess * Benign polyp * Plasmacytoma * Eosinophilic granuloma * Undifferentiated oral malignancy DIAGNOSTIC PROCEDURES * Laboratory results are usually normal. * Skull radiography may show areas of lysis surrounding the alveolar bone. * Consider thoracic radiography to detect pulmonary metastasis (uncommon). * A large, deep tissue biopsy (down to bone) is required for diagnosis. TREATMENT OPTIONS AND PROGNOSIS * Radical surgical excision required (ie, partial mandibulectomy or maxillectomy) and usually well-tolerated by patients. * 1-year survival after excision in dogs--25% to 45% * 2 year-survival after excision in dogs--20% to 35% * Median survival after excision in dogs--from 7-11 months. Survival improves when excisional margins are free of neoplastic cells. * Mean and medial survival in dogs after excision and radiotherapy--7 and 8 months, respectively; range, 0-27 months. * Mean and median survival in cats after excision--2.5 and 14 months, respectively; range, 0-36 months. * Median survival after excision and radiotherapy in cats--14 months (range, 1-36 months). * Outpatient chemotherapy with cisplatin, carboplatin, mitoxantrone or doxorubicin is palliative in dogs (cisplatin is contraindicated in cats). * Outpatient use of COX-2 inhibitors such as Piroxicam are considered palliative and may cause partial or stable responses. * Cause of death related to local recurrence and secondary anorexia and cachexia. FOLLOW-UP * Repeat head and neck examination by survey thoracic radiography at 1, 2, 3, 6, 9, 12, 15, 18, and 24 months after treatment * The overall prognosis is poor in cats because most are locally invasive and diagnosed late in the course of disease. WHAT DO WE DO AT GULF COAST? * Following appropriate clinical staging, if complete surgical excision is considered possible - we do it! * If microscopic tumor remains following excision - radiation therapy is considered and our 1-year+ survival is >70%. * If surgery is not possible - we consider radiation therapy combined with mitoxantrone chemotherapy to shrink the tumor, then consider surgical removal of remaining tumor with a 1-year+ survival >50%. * If palliation is considered, our best protocol includes Piroxicam with or without Mitoxantrone chemotherapy. Don't hesitate to call or email us at Gulf Coast Veterinary Oncology! Drs. Hahn, King, Cerraras, Freeman and Turner are available for consultation Monday-Friday at our Houston, Tomball and San Antonio locations. ALL THE BEST, Kevin A. Hahn, DVM, PhD Diplomate ACVIM (Oncology) & Overall Nice Guy Gulf Coast Veterinary Specialists 1111 West Loop South, Suite 150 Houston, TX 77027 P: 713.693.1166 F: 713.693.1167 http://www.gcvs.com mailto:drhahn@gulfcoastvetspec.com