So you are implying Religion saved them?

Because other them that, I cant See any reason why people who survived cancer should be more religious than ones who didnt.

If anything, they should be less Religious and more sceptical, since their prayers either didn't help their cancer, or they denied all treatment recognizing that - since their God is all knowing and everything bad that happens to them happens for a reason, therefore - making Human intervention like medicine a sin and detaching from god, died. And the only ones remaining were the ones who recognized that God dosent exist and we already live in the 9th circle of hell.