Oh boy, I wish the news was better. Poor Cincy. But, she'll endure this and may be just fine after the second surgery:

My Oreo had a similar kind of non-metastasizing (local), slow-growth cancer in her front leg in 2004. And like Cincy, the first surgery didn't get clear margins. We did the exact same thing--wait 30 days, and then have another surgery to take a wider sample to get any remaining bad cells and very clear margins. This worked--it hasn't grown back in 4 years.

I hope that this is what happens for your Cincy as well. I'll be thinking of you and her over the next month. It seems like a long time to wait, doesn't it? Hang in there, and give Cincy a big hug.