Intercessory prayer is pointless

[SteveII]

Nope. I am a Molinist (God's middle knowledge lets him see what people will freely choose to do). Free will lives on. 

You are asserting that God caused the cancer. It might be that you simply chose to smoke or go to the beach. So, I don't accept that God caused any cancer. Actually that's not a belief that Christians generally hold (if at all)--so it is a straw man argument.

But your god knew that you would, you had no choice in the matter.

That does not make sense. I know my wife will choose chocolate ice cream over butter pecan every time. Does that mean she is not exercising free will? God derives his knowledge of what we will do given every actual and counterfactual circumstance because of his perfect predictive knowledge.