The schools of veterinary medicine are excellent resources. Many provide cutting edge information about advances in veterinary oncology, and about treatment and care for a pet with cancer. Some are conducting clinical trials that might be of interest to you.
Each school has a treatment center and an oncology department. The small animal hospitals are part of the University academic programs for students studying to become vets. They are staffed by students and veterinary oncologists.
For more information about a particular school or treatment center, contact the school nearest you directly.