Primary frontal sinus squamous cell carcinoma in three dogs treated with piroxicam combined with carboplatin or toceranib

In human medicine, primary frontal sinus squamous cell carcinoma (pFS-SCC) is not frequently reported. In veterinary medicine, frontal sinus SCC is exclusively described as an extension of nasal cavity SCC. To our knowledge, this is the first publication concerning canine pFS-SCC, diagnosed using histology or cytology and medical imaging, in three dogs. The tumours extended into the orbit or brain cavity, without nasal involvement. Treatment was initiated with piroxicam-carboplatin. Prolongation of carboplatin delivery with a low dose intensity was performed on dogs with a favourable initial response. Dog 1 achieved a complete remission (CR), but was euthanized 344 days after start of therapy. Dog 2, still alive 3 years after start of therapy and in CR, received 14 carboplatin deliveries. In dog 3, after changing the treatment protocol into piroxicam-toceranib, a significant tumour reduction occurred, but the dog was euthanized after 195 days because of a relapse.