Apply sunscreen when you take your dog outdoors that is made specifically for dogs. Don't use human sunscreen. Pay particular attention to the nose and ear areas and to dogs that have thin coats and pink skin. There's no sure way to prevent cancer, but there are other steps you can take to keep your dog as healthy as possible. Feed a high quality kibble or homecook. Use bottled water or install a water purifier. Follow the new vaccination protocols. Avoid polluted areas. Don't smoke - it's as bad for your dog as it is for you. Go green in the house and garden. Don't use chemical, use natural products - vinegar and baking soda are excellent cleaners. Keep your dog at a healthy weight. Try natural flea and tick products such as Natural Defense. Exercise your dog daily. Have regular checkups at the vet.