How to prevent your dog from getting cancer?

I am very concerned about protecting my dog from cancer. He is 9 years old. My previous dog died of colon cancer at age 11 and I want to do everything possible to prevent such fate to my current dog. Please advise as this is a very big issue for me. Thanks a lotvet does not take my concern seriously and changes topic when i ask. He says, "dog's health is good. congratulations"

Talk to a verternarion. Sorry if I spelt that wrong. The vet.

My answer: Blue berries! The have cancer fighting antioxidants in them!! Just chunk a moderate amount in his food everyday I know somebody that fed their rat a blueberry a day and he lived to 9. most rats die from cancer at around 3. So thats my 2 cents! Good luck hun and smile on!