Hi, I am so sorry that you are put in a position to have to make this decision.  I kind of sat on my response because I didn't want to sound harsh but I do think this needs to be said. 

Yes these are very tough decisions. We thought about it and decided against chemo. It may not be a magic bullet that cures Romeo – it may or may not even give you more time. Each dog is different and what may be right for one dog could be wrong for another.
I just don't want you to feel bad at all if you choose not to do chemo.  You can't explain to an animial what or why you are doing this – As Jerry says – dogs live in the now – not in the what if. 

For us it was a quality of life question as well. I worked for a woman who's cat had feline leukemia and aids. She went the extra mile – did everthing possible – mortgaged her condo. What did that mean for the cat – chemo – daily IV's – countless meds – hair loss – weight loss – sickness – for all of her heroic efforts this cat had no quality of life – it couldn't even be a cat tied to IV's all day. In the end she bought another year for this cat's life – but what kind of year was it from the cat's perspective.

When we got Radar's osteosarcoma diagnosis, we decided we were not going to do that to him. He may have 6 months – he may have 3 years – but darn it those months or years were going to be spent being a happy dog and being loved and played with. 

Radar just past his one year ampuversary – and is doing awesome. Guess we made the right decision for him.