Cancer preventable? I don’t think it is necessarily binary. More complicated than that.
Cancer is but one expression of genetic weakness - I.e. disease - in the presence of antagonists, be they chemical (including self-induced inflammation), biological or radiological.
I can prove it: Look at the incidence of cancer in this country compared to other, non -westernized countries.
The ONLY explanation is that our current state of so-called “epidemic of disease” is self-induced.
That’s overly-simplified, but I’m neither writing a book in a comment nor responsible for convincing anyone of that which is proved around me on a regular basis.
If cancer can be reversed - permanently - with no pharmaceuticals or chemo, then it can be prevented.
I know people who have achieved this and anyone with internet can find anecdotal evidence of such. Prolific, in fact. The problem is that if they cured cancer, there’s be no profit in that field.