I have never heard of one. When a cat gets cancer, whether in the kidneys, bowels, or elsewhere, it is usually so far advanced and has spread to the lymph system that it is fatal. Cats are SO good at hiding pain and sickness that everything they get is advanced. Even when the cancer tumor is removed and radiation/chemo is administered, it usually just buys a short amount of time. And to tell the truth, the stress of all the surgeries and procedures is not helpful either. When any living creature is existing and not really enjoying life anymore, please find it in your heart to end that pain. Thank God we can. I have witnessed MANY humans suffering at the end of life.