I am sorry for the delay in replying to your question, since time is important in these decisions. Real life sometimes intrudes on my cyber-life. There is not much question that the combined chemotherapeutic approaches to lymphoma work markedly better than prednisone alone. The mean survival times for combined protocols is between 12 and 18 months at the current time. The most commonly recommended protocol is the COAP protocol described in Kirk's Current Therapy X, I think.
Most dogs tolerate chemotherapy fairly well.
I think it is legitimate to question the merits of extending life for a relatively short period of time but that is a question that you have to answer for yourself. Everyone feels differently about the importance of those months. When chemotherapy works well, most owners are glad they tried it. You have to make up your mind in advance which approach is best for you and your dog and then try hard not to second guess yourself too much. You should be able to get the most recent information on chemotherapy from ISU's oncologist or internal medicine specialists.