This is a linkpost for https://entirelyuseless.wordpress.com/2017/03/04/the-practical-argument-for-free-will/
You are confusing things and probabilities. Getting cancer largely depends on having the lesion or not. But the probability of getting cancer depends, not on the thing, but on the probability of having the lesion. And the probability of having the lesion is mutable.
Getting cancer largely depends on having the lesion or not. But the probability of getting cancer depends, not on the thing, but on the probability of having the lesion.
Let me quote your own post where you set up the problem:
90% of the people with the lesion get cancer, and 1% of the people without the lesion get cancer.
This is the probability of getting cancer which depends on the "thing", that is, the lesion. It does NOT depend on the probability of having a lesion.