I'm so sorry this isn't the news we were all hoping for.
I know Carlo is one strong fellow, and I have faith he'll tolerate the chemo regimen very well again! My bullmastiff would actually take the chemo pills (cytoxan) directly from my (gloved) hand. Crazy boy. He wasn't bothered by the oral chemo meds at all. It was nothing like the adriamycin (iv) treatments where he would usually sleep all the next day. Of course, that could have been from exhaustation after being hooked up for 8 hours surrounded by yappy dogs at the oncologist more than the drug itself. He also did injections of vincristine without side effects.
They do remarkably well on chemo, but I don't think I need to tell you that when Carlo is pulling for 2 mile walks!