Even I ate better foods (traditional Polish/Ukrainian cooking) than the kids today do. I can just imagine what the cancer rates will be by the time they reach my age with all the instant crap with more chemistry on the label than actual food their parents feed them today.
I believe age has a lot to do with it. The more you age; the more likely you are to encounter a disease. My 19 year old cat just passed due to a nose tumor. They are rare in cats. Hers was discovered 2 days before she died. All of her vital organs were better than her age told. My vet said that they are seeing a lot more cancer in older patients. She also said the cancer cells can mutiply very fast.