"too young/fit/healthy to get cancer" how do I react when I get told this by someone even though there is literal proven evidence that rates of cancer, especially blood, breast, skin and bowel cancers, are rising steadily in younger people?

It's at this point where I feel like it's not just my health anxiety and that I do realistically have to prepare myself for that conversation with a doctor or a nurse where you're told that you've got six months left to live because of a late cancer diagnosis. It feels like there's so many different factors that can cause someone to develop cancer, and I'm finding that every time I use my roll on deodorant, walk in town past someone who is smoking, briefly inhale car fumes when I'm at a road crossing, eat red meat etc. the smallest every day things which I never would have really payed more than a seconds thought to before, now cause me a lot of anxiety if that makes sense. This genuinely isn't meant to be a bullshitting or spam post, just someone who's genuinely looking for some rational context as to how alert I should be about C in general. Btw it doesn't help that in my family I feel like there is kind of a thing where other family members only talk about or raise/share info about any health concerns or diagnoses(cancer etc.) when it "has" to be spoken about as in when it's at a later stage or later time down the line. For this reason, I constantly feel like I can't relax due to having a feeling that if a family member has C then I would never know because they wouldnt inform other family members etc.