Karma is the root cause of all success or failure in life. Once the negative karma has been removed, cancer won't return. I suggest your reading any of the Soul Power Series of books by Dr. Zhi Gang Sha. Most people do not know that hurting others, stealing, taking advantage of others, killing, harming others causes karma. We learn lessons in the form of illness, accidents, broken relationships, financial challenges. Do a little harm, you learn a small lesson, do more harm and you learn a larger lesson.