Well, just to update everyone- I'm back home. The surgery was uneventful, and the the docs remarked that aside from the cancer, my mom is in amazing shape! The cancerous area was very small, and there's no sign that it spread to any other tissue, nor into the lymphatic system. She's expected to recover fully with no need for chemo. With luck she'll be released on Fri or Sat. She'll have to stick to clear liquids for a few days, then transition to smoothies and the like for a few more days, then she should be right as rain.
Thanks for the well wishes, everyone. It really gave me a good kick in the @ss and rattled my sense of complacency! But hopefully the worst is behind her now.