Only you can know what is right for your dog, you, and your budget. But I will tell you that I had an 11 year old Italian Greyhoud with Lymphoma, I did the chemotherapy, and extended his life about 3 years.
He was a precious dog who I still miss and it’s been about 5 years. The chemotherapy only cost me about $1800. Many people I know thought I was crazy and it was outrageous to spend that money on an 11 year old dog.
The last 6 months of his life were difficult for him. I probably should not have dragged it out. In the end, he developed vein tumors on his legs that we had to keep wrapped because they bled. The last month he was on pain pills. I have come to regret putting him on pain pills and not letting him go in peace sooner. Looking back I think it was bad of me to put him on the pain pills because he was in pain and couldn’t let me know if the pills were helping or how much. Dogs act differently in pain than humans. It’s not easy to know if they are ok.
I finally made the decision to end his suffering. Of course he was like a happy puppy the Saturday we took him to the vet. It haunts me. I wish he would have gone naturally. I did not want to make that life and death decision. Don’t know if this helps or not.
During his treatment, I would ask my Vet if I should put him down, she told me that I would know when it was time. I do believe Lymphoma is a quick death if left untreated.
So sorry for your puppy and you.
Please tell me you have adopted another dog!