It was stage 1 when first diagnosed. Her prognoses was great but they left some cancer cells behind and untreated, within that short amount of time it spread to her liver and lungs. And no, oxidization can create free radicals that break down healthy cell structures, damaging the DNA and promoting the development of cancer. The more free radicals present, the more cancer causing damage occurs. Kind of like when you cut into an Apple or a banana and the sugar reacts with the oxygen, causing that brown discolouration.