In an animal presented for evaluation of an oral tumor, the extent of the disease is based on the systematic evaluation of the tumor, including diagnostic imaging, and the assessment of regional lymph node involvement and distant metastases. The nature of the disease is determined by an incisional biopsy and histopathologic examination. The choice of treatment and expected outcome are based on the stage and expected biologic behavior, which is well known for many oral tumor types. The various mandibulectomy and maxillectomy techniques have been shown to give good functional and cosmetic results.