Good News!
The tumor on my grandmother's arm is completely gone. They're going to give her the last two rounds of chemo anyway (a "just to be safe" measure), there's going to be a test to make sure the lymphoma didn't spread into her bones (we doubt it did, but checking is the smart thing to do) and because of her age, they're going to do a test to make sure the chemo hasn't affected her heart.
There's even a chance she'll have to undergo a little radiation once chemo's over. But given the advances in medicine (they gave her another drug with the chemo that kept all the side effects aside from losing her hair away), I'm told radiation isn't that bad anymore.
And it bears repeating: the tumor in my grandmother's arm is gone.