Cancer

Cancer is an awful disease that attacks people in many cases for reasons unknown. Why does it choose one person over another? I know a rhetorical question. But when it strikes your family you often wonder why. I know some of the reasons it struck my father, he is and had been for too many years a heavy smoker. But I question why some smokers never get cancer, and yet live to be 100. It seems that cancer is random, it is like play Russian roulette. Will the cancer bullet strike this one, or that one?
I know this is a tough subject, but I am wondering about it and I am questioning the treatments, the diagnosis, the death sentence if you will that is handed out by doctors. Do they really know who will live and who will die and how long someone will live? I mean first it was a year, then six months, and now a year again. It is as if we are simply puppets in the game they play and the lives of our loved ones are what is at stake.
Why is some people dance through treatment and others drag? Why do some die quickly and others linger for years?
What is death really? Is it the beginning of a new life or just the end, period.
I would really like to know the answers to my questions, but the only one who can answer them is God and though I trust in him, there are days I feel he is not listening. I know that he only gives me as much as I can handle, but why, oh, why, does he think I can handle so much?