I went thru lymphoma with my first grey, Rascal. I opted to go thru chemo. He was my first dog and the love of my life. Yes, there is a definate cost consideration. I worked with a local oncologist here in Cincinnati and we went thru three different drugs. Eventually each one would lose its effectiveness. The last one was kind of a hail Mary which had side effects. The first two didn't effect his quality of life at all. He was a little more tired the days he went thru treatment. But the treatment was just an IV port that allowed the to directly put the drugs into him. It was pretty quick and painless. The last drug basically drove his white cell count down too far and we ended up at the ER for a night of fluids and massive antibiotics. The vet thought it was time for euthansia then and I said no. He lived a total of 15 months from diagnosis and six months after we stopped treatment. I would do it all over in a heartbeat.