My 12 year old dog has a 6.3 cm mass on his spleen. There might be 3 or 4 mm sized nodules on his lungs but it is not definite (as seen from chest x rays). From his full blood panel and wellness exam, he has a strong heart and his blood work appears fine. Is it worth the trauma of doing the surgery to remove his spleen? If we don't do the surgery will it be a painful death for him? I hate to consider euthenasia since he is still seeming to be happy - enjoying his walks, eating, etc., but I don't want him to suffer.