Canine Tonsillar Squamous Cell Carcinoma – A Multicentre Retrospective Review of 44 Clinical Cases

Objectives: To establish whether presenting clinical signs had prognostic significance in dogs with tonsillar squamous cell carcinoma (TSCC); to evaluate the impact of surgery on outcome and to compare the survival time of animals that received multimodality treatment with those that did not. Methods: The medical records of 44 dogs were reviewed retrospectively. Clinical signs, clinical stage, time of diagnosis, treatment and outcome were recorded. Data were analysed using the Kaplan-Meier, logrank, Student’s t test, Kruskal-Wallis test and Chi-square/Fisher Exact and Cox’s proportional hazards methods as appropriate. Results: Of all recorded presenting clinical signs only anorexia (p=0.02) and lethargy (p=0.015) were significantly associated with a poor outcome. Median survival time for all the dogs in the study was 179 days. Surgery increased median survival times in dogs that did not receive chemotherapy (with or without radiotherapy), but did not significantly increase the survival time (p= 0.079) in dogs receiving multimodality therapy. Administration of chemotherapy with or without radiotherapy significantly increased the survival probability (p< 0.01). Clinical Significance: Dogs with TSCC with anorexia and lethargy have shorter survival times than patients not showing these clinical signs. This study indicates that chemotherapy (with or without radiotherapy) may significantly prolong survival time in dogs with TSCC.