My 8 year old Great Dane was just diagnosed with lymphoma this past Wednesday after I found that the lymph nodes under his neck were swollen... once I got him to the vet they found that all his lymph nodes were swollen. About two weeks prior to that, he had two very small mast cell tumors removed. Tomorrow we go to the oncologist to see what stage he's in and if he's a candidate for chemo not based only on what stage the cancer is in, but also due to his size, age, and the fact that he has also developed a heart murmur which may be signs of heart issue in addition to the cancer. I don't know how to make the right decision.... no treatment? Prednisone? Chemo? I have guilt over which ever I choose, or don't choose. I only care about doing the right thing for him, not for myself. How do you KNOW?