Cancer in Golden Retrievers

In today’s pet corner of my newspaper I found out that Golden Retrievers are having a lot more cancers than other dogs. A reader asked this question and the answer was given by a board certified medical oncologist and graduate from a University of a State College of Veterinary Medicine. First this sounded very impressive to me, like an authority seriously answering a serious question. Then I read the answer. And then, I googled “oncologist” because, I have to admit, after reading the answer I wasn’t 100% sure anymore as to what they are doing for a living. For those of you who too want to admit that they are not quite sure what these guys are about, here is what Wikipedia says: “Oncology is the branch of medicine that studies tumors (cancer) and seeks to understand their development, diagnosis, treatment, and prevention. A medical professional who practices oncology is an oncologist. The term originates from the Greek onkos (ογκος), meaning bulk, mass, or tumor and the suffix “ology”, meaning "study of".
Ok, now since we made sure that an expert was answering the Retriever owner’s question, let’s take a look at the answer, or shall I say lack thereof? Here it is:
“You made a very interesting observation. The answer to your question is “Yes”. Golden Retrievers do have a higher risk of developing cancer than other breeds. They tend to have a higher rate of mast cell cancer, lymphosarcoma, osteosarcoma and hemangiosarcoma. If you have a Golden Retriever it is recommended to take him/her to the family vet every six months. And finally, (Comment: What a relieve), it is not guaranteed that it will be diagnosed with cancer. The oncologist has a Golden too. They are wonderful dogs.”
I only have to say this: If I would answer my customer’s questions like this I’d be out of business by now. I have not learned anything but a few new fancy Latin words for some disease, which I now have to look up in the dictionary. I have not learned why they exist, why the dog is more receptive to them than other breeds and what can be done about the disease. And my final question is: What do you mean by “not guaranteed…” Does that mean Goldens usually come with cancer? Is there something wrong with mine because he doesn’t have it?
I personally would add: Is it ok that I keep feeding my dog the cancer causing food I am buying off the supermarket shelves for $30 per 50 lbs.?