Sorry to hear this news, I know how devastated you are.
Our top Scottish Terrier, Shorty, is not even three years old and he was just diagnosed with non Hodgkins lymphoma. We had the choice of either euthanizing him right then or putting him on human chemotherapy protocol. He went on the chemo and immediately went into 100% clinical remission. About 50% make it to one year until the cancer cells become resistant to the drugs. His quality of life has been excellent though but the cost is about $500 per month. Good thing I went to veterinary school and have many oncologist friends so I can get the used human chemo drugs for cheap to give to him.
Just one year ago, one of our Scotties (Terra) got killed by an 8 foot alligator in our backyard, so this was not welcome news.
Attached is a pic of Shorty (Black), Terra (White) and Zoe one of our duck-quail-dove-snipe hunting English Springer Spaniels .
Remember, our pets are just a microcosm of our world, everyone will experience what they are experiencing, some sooner and some later, but virtually no one escapes. Take the time out to love and learn during this experience....