Please see my thread "Scooby's Story A Tale of Hope" in the Fighting K-9 Cancer Group.
Your story sound very similar to ours. A little over 2 1/2 years ago, Scooby was diagnosed with advanced canine lymphoma and given 4-6 months t o live. The vets at the University of Missouri Veterinary College said it wasn't curable, too. But today, he's still with us, still active and shows no signs of the dreaded disease. Keep the faith. Miracles do happen.