certain cancers like breast or thyroid and certain stomach are genetic.

For everything else age is a huge factor. It’s usually in late 60s a person gets more chances of cancer as your cells age and create mutations.

Certain life styles such as HPV are on the rise because of …well basically free loving in the 70s/80s prior to the vaccine. This is why you’re suddenly seeing a huge spike in throat cancer right now in 60 yr olds. Especially men and a lot of women are getting cervical cancer right now as gardisil was not around when they were most sexually active.

And then you have certain hernias as you age are likely to happen that can lead to stomach cancer as your cells will make more mistakes to try to heal these hernias.

Basically your cells heal. And each time they heal they increase in chances of mutation of becoming cancer. This becomes even more so as you age.