Partial
mandibulectomy was performed for the treatment of benign or malignant oral
tumors in 142 dogs. Forty-two dogs with a benign
tumor (
ameloblastoma) had a 22.5 month (range, 6 to 74 months) median disease-free interval, with a 97% 1-year survival rate; there was local recurrence in one dog. Twenty-four dogs with
squamous cell carcinoma had a disease-free interval of 26 months (range, 6 to 84 months), with
a 91% 1-year survival rate; recurrence and
metastasis developed in two dogs and metastatic disease in one dog. Based on survival curves, 37 dogs with a
melanoma had a median survival time of 9.9 months (range, 1 to 36 months), with a 21% 1-year survival rate; 20 dogs died or were euthanatized for recurrent or metastatic disease. Twenty dogs with
osteosarcoma had a median survival time of 13.6 months (range, 3 to 28 months), with a 35% 1-year survival rate; nine dogs died or were euthanatized for recurrent or metastatic disease. Nineteen dogs with
fibrosarcoma had median survival time of 10.6 months (range, 3 to 32 months), with a 50% 1-year survival rate; 12 dogs died or were euthanatized for recurrent or metastatic disease. Results of this and previous studies demonstrated that partial
mandibulectomy was effective in prolonging survival and decreasing recurrence for
squamous cell carcinoma and
ameloblastoma. Progressive disease and corresponding low survival times were common in dogs with
melanoma,
osteosarcoma, and
fibrosarcoma. There were no differences in survival times or the progression of disease among five partial
hemimandibulectomy procedures. The high rates of recurrence and
metastasis in dogs with these
tumors suggest a need for evaluation of ancillary
chemotherapy and local
radiation therapy to decrease the prevalence of progressive disease.