What is the theme in It's Not About the Bike by Lance Armstrong?

Cancer survival is a main theme throughout the book. Lance has a goal from the minute he is diagnosed that he will beat the disease, even if it is against all odds. One learns late in the book that Lance had very low odds of survival. The description of survival in the book is that it is something one actively takes on. One cannot just sit back waiting for it to happen, but must believe it, whole mind and heart.