Clinical staging for oropharyngeal malignancies in the dog

One hundred dogs bearing malignancies of the oropharyngeal region were examined over a three‐year period and prospectively staged using the World Health Organisation TNM Classification of Tumours of Domestic Animals. Primary tumours were characterized by their large size or local infiltration (71 per cent, T3 status) and invasion into adjacent bone (60 per cent, Tb status). Regional lymph node metastasis was less common (17 per cent, N1b, N2b or N3 status) and distant metastasis was an unusual presenting feature (5 per cent, M1 status). The early Stage I and II tumours together accounted for 8 per cent of the total series whilst the more advanced Stage III group were by far the most frequent, representing 84 per cent. The remaining 8 per cent being classified as Stage IV because of extensive regional or distance metastatic deposits. Prognoses by stage showed actuarial survival rates at 12 months of 100 per cent for Stage I, 71 per cent for Stage II, 31 per cent for Stage III with no survivors in the Stage IV group. Survival rates for the major histological types were 44 per cent for the non‐tonsillar squamous cell carcinoma, 22 per cent for the tonsillar squamous cell carcinoma and fibrosarcomas, 17 per cent for mastocytomas whilst none of the malignant melanomata survived 12 months.