Dammit. I thought I was being all rational and sensible about this Fishy cancer thing: I love my kitties but try not to be sentimental about them. The vet just phoned, and it's the worst case scenario. As he thought, Fishy has a squamous cell carcinoma on the roof of her mouth, starting to work up into her brain, and it's untreatable by either surgery or chemo. The best case scenario is that she'll last about 6 months before her quality of life deteriorates to the point where we'll have to put her down; worst case scenario, it could be weeks.
I thought I'd accepted the likelihood of this outcome and dealt with it over the last week. Nonetheless I type this in a rational, sensible, unsentimental fashion, telling myself that we can minimise her suffering, she's had a good and comfortable life, and that serious feline cancer treatments would financially cripple me, in floods of tears.