Update: I talked to the doctor, and he didn't feel any enlarged lymph nodes in her armpit, so that's good. He also felt he got pretty good margins on the tumor, and didn't leave anything behind. That isn't to say that it hasn't already spread and we just don't know it yet, but at least the primary tumor is gone.
On another troubling note, Cookie has been battling periodic kidney infections, and the urine sample the doc took yesterday still had lots of blood cells in it even though she's been on antibiotics for a couple of weeks. He's concerned that there's something sinister going on somewhere in her kidneys and/or bladder, and wants a radiologist to ultrasound the bladder and kidneys to see what's going on.
Since there are several board-certified radiologists on staff at my hospital, I'll have one of them take a look at Cookie while she's here visiting the oncology service. I think my mom is going to drive her down this weekend, provided we get the histopath results back. I'm so anxious about getting the ball rolling, I don't know if I can wait. I just want to find out everything that's wrong, and do what we can to fix it or make her comfortable for whatever time she has left.