Age

It is said that age is the single biggest risk factor for cancer and while one can get cancer at any age, the highest rate occurs in decades 6-8. This fits with the view that cancer is a multistep process  with genetic mutations or alterations in our DNA which involves going from a less malignant to a more malignant and invasive disease. The longer our exposure to carcinogens the longer we live, genetic mutations and tumors taking years to develop, and the ability of our immune systems to combat cancer as we age are thought to create these changes.