My Paxil has had two bouts with Mast Cell Cancer. She's 10 now and doing just fine.

How old is your dog and what breed is she? Boxers are particularly prone to more aggressive Mast Cell tumors.

Was the surgeon able to get 2cm of clean tissue on all sides of the tumor? The first time Paxil had one removed, they weren't able to do that. It was back in under a year and in 3 spots. All of those were removed with clean margins and so far no reoccurances. Mast cell tumors, as my vet puts it, get "ticked off" once they are touched. So any cells left behind will be likely to reoccur.

What was the tumor graded at? Grade one Mast Cell is relatively benign. Removing the tumor is usually all that is needed. Grade 3 means the cancer has invaded other tissue and the prognosis isn't great. Grade 2, which is what Paxil has, is the most unpredictable. Additional treatment may be needed to ensure it doesn't come back, if it's available in your area. Where I live there is no access to radation or other cancer treatments(even humans with cancer have to travel to get treatment).

Generally speaking, if your vet got clean margins around the tumor, your dog should be fine. Good luck!