This is a linkpost for https://entirelyuseless.wordpress.com/2017/03/04/the-practical-argument-for-free-will/
What matters is the probability that you will get cancer, period
That probability happens to depend on whether you have the lesion or not.
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.