Both my BCs have come to the surface after times of intense stress. There were ten years between them, which tells me that the disease never went away but my immune system was able to cope with it. Until things went wrong.
I wasn't surprised when I was first diagnosed. I wasn't surprised when it came back. I was, and still am, a drinking, smoking rooting, tooting piece of work. On occasions I'm a great big fat example of bad health. Sometimes I'm an unstoppable exercise junky who does wicked things when there is wine, food and drugs around. Phfft. Does it really matter? Sort of like pranging the car then having buyer remorse because you bought the wrong model.
Rear view mirrors are useful until you hit something you didn't look for. Then it's too late.