Role of carboplatin in multi-modality treatment of canine tonsillar squamous cell carcinoma--a case series of five dogs.

Canine tonsillar squamous cell carcinoma is an aggressive disease with a poor prognosis. A retrospective study was undertaken of all dogs that were presented between January 1999 and January 2004 to the Animal Health Trust for the treatment of tonsillar squamous cell carcinoma. Five cases were identified, and their median survival time was 211 days (95 per cent confidence interval 80 to 352) with two of the five dogs remaining alive at the end of the study, 826 and 1628 days from diagnosis with no clinical signs of disease. The protocol was well tolerated with only one of the five dogs showing toxicity associated with carboplatin and all dogs that started radiotherapy completing it. Compared with results of previous studies, these cases suggest that surgical cytoreduction followed by coarse fractionated radiotherapy together with carboplatin may be a useful way to treat this tumour. Carboplatin alone caused partial remission in the two cases where it was used as neo-adjunctive therapy.