What is the life expectancy for an 11 year old Miniature Pinscher (male) with Lymphoma in his left lung?

I am very sad and scared to say that my best friend of 11 years was just diagnosed with Lymphoma in his lungs. A mass was identified on a chest x-ray in his left lung as well a spot in a secondary lobe. He was exhibiting many symptoms such as coughing, wheezing, shaking, loss of appetite, lethargy, and stomach upset. I had a single dose of chemotherapy given by injection 5 days ago and he is remarkably better. Like a new dog! Does this mean that I could continue these treatments for the next year and expect the same results and quality of life for him. The medication was alsparze.