Complete surgical excision affords the best chance of a cure for most oral malignancies. Epulides do not metastasize and, if small, can be cured with excision alone. When multiple concurrent epulides occur in cats, they are more likely to recur after excision than in dogs; thus, wide excision is advised. ³⁷ Rostrally located malignancies have the best prognosis; thus tumors in this location, including those on the tongue, should be excised with curative intent. ¹⁸ Even with excision of over half of the mobile portion of the tongue, dogs can maintain the ability to eat and drink. ^6,28,38 Cats, on the other hand, may not tolerate extensive oral surgery as well and may have problems with prehension or compromised grooming ability after partial glossectomy. Results of surgery are summarized in Table 20-2 . ^5,5,39-47 As long as surgical margins exceed 2 cm, complete maxillectomy or mandibulectomy may not be necessary. In one study, case outcome was similar regardless of the extent of surgery (radical vs. limited) for dogs with MM. ⁴⁶ Considerable shrinkage of the surgical margins occurs after excision, formalin fixation, and slide preparation of lesions from the tongue and labiobuccal tissue. In fact, surgical margins of 8 to 10 mm are necessary in order to obtain clean histologic margins of 5 mm. ⁴⁸ This should be taken into account when evaluating histopathology reports after resection and may alter interpretation of literature citing necessary surgical margins at these sites. Owner satisfaction with partial maxillectomy or mandibulectomy in dogs was 85% in one report. Owners perceived that the surgery afforded pain relief and were most pleased with results of rostral mandibulectomy, as compared with partial maxillectomy. ⁴⁹ Gastrostomy tube placement may be an important aspect of postoperative and palliative care. Dietary management with gastrostomy tube placement is reviewed in Chapter 18, Section B . Cryosurgery can provide good results for small (<2 cm diameter) lesions with minimal bone invasion. ^5,6,50,51 Complications such as oronasal fistula or bone necrosis and fracture may occur when cryosurgery is attempted for larger tumors.

Radiation therapy may be used with curative intent for small SCC and epulides, for localized tumors with microscopically incomplete surgical margins, and as a palliative option for unresectable masses, including those crossing the midline of the hard palate. Results with radiation are summarized in Table 20-2 . ^52-61 Response rates are generally best for SCC, although in one prospective clinical trial of megavoltage irradiation for 105 dogs with oral SCC, FSA, or MM, the only prognostic factor identified was tumor size regardless of tumor type. ⁵² Therefore, radiation therapy is most likely to be effective when used early in the course of treatment of oral tumors rather than for salvage therapy against large tumors late in their clinical progression. Although radiation response may be short-lived, it is sometimes possible to re-irradiate tumors that do respond, in hopes of achieving a second positive response. ⁵³ Both coarse and fine fractionated radiation protocols (see Chapter 15, Section A for definitions) have been evaluated for treatment of oral tumors. Once-weekly fractionation provides similar clinical responses to standard fractionation for dogs with MM and those with non-resectable soft tissue sarcomas. ^54,55 Accordingly, this option may be considered in an effort to prevent extended hospitalization. Coarse fractionation is not recommended for cats with oral cancer because of poor efficacy and unacceptable treatment complications. ⁵⁶ Hyperthermia improves response to radiation therapy, but is labor-intensive and not readily available. ³³

Because local disease progression, rather than metastasis, is often the reason for deaths associated with oral malignancies such as SCC and FSA, systemic chemotherapy may be less important than localized therapy. Adjuvant chemotherapy with mitoxantrone, 5-FU, and cisplatin has improved responses of human head and neck cancers to radiation. These drugs may also prove useful as adjuvant therapy for small animal patients, but published veterinary reports are rare. Neither cisplatin nor 5-FU should be used in cats because of the potential for drug-related fatal toxicity. Improved response rates for non-resectable feline oral SCC may be achieved by combining radiation and mitoxantrone (median survival time = 6 months; 30% 1-year survival ^∗ ) or gemcitabine chemotherapy. ⁶⁰ Chemotherapy alone has traditionally offered little benefit in terms of clinical outcome for oral tumors in dogs and cats. Carboplatin has been used to treat oral MM and SCC in dogs with non-resectable tumors. ^62,63 The non-steroidal anti-inflammatory drug (NSAID), piroxicam, has shown some promise as a palliative treatment for oral SCC, both as single-agent therapy and in combination with chemotherapy. ^63,64 A dose of 0.3 mg/kg/day PO in dogs and q48h in cats may be used if renal function is adequate. Because gastric ulceration may result from the use of NSAIDs, some advocate concurrent administration of a prostaglandin analogue such as misoprostol. Reported results with chemotherapy for oral malignancy are summarized in Table 20-2 . ^{5,8,59,60,62-70} In an unpublished report, a protocol combining bleomycin (20 mg/m ² SC on days 1–3, then weekly for a maximum of 20 doses) and methotrexate (15–20 mg/m ² SC weekly on a 4 weeks on/4 weeks off cycle) resulted in an 87.5% overall response rate in 8 cats with SCC (5 CR and 2 PR). ^∗ Given this dramatic response rate and the reported lack of serious side effects, further evaluation of this protocol is warranted. Intralesional chemotherapy, usually with cisplatin, has been evaluated for treatment of oral tumors, including canine MM. ^71,72 In one report, bleomycin (5 mg) was injected intralesionally once weekly to four dogs with recurrent acanthomatous epulis. All dogs responded, with complete responses in three dogs lasting over 1 year. ⁷² Intralesional chemotherapy is discussed in Chapter 12, Section E .

Photodynamic therapy (PDT) (see Chapter 17 and Figure 14-2 ) shows promise in the treatment of oral SCC in dogs. ^73,74 The treatment requires less hospitalization than radiation therapy and provides excellent cosmesis. In contrast, our experience with PDT for treatment of oral SCC in cats has been disappointing to date.

Immune enhancement techniques are the focus of active research and are covered in greater detail in Chapter 16 . For the oral tumors that occur in veterinary patients, immunotherapy is most promising for MM. ^75-78 In 2007, the U.S. Department of Agriculture granted conditional licensure for a canine melanoma vaccine that is intended for use in the minimal disease setting, after the primary tumor has been locally controlled via surgery or radiation therapy. The vaccine is initially being made available only to board-certified oncologists.