Play smart and don't worry yourself sick about cancer... Its one of the stupidest fears people some times fall into, its the same as about any other possible illness, listen to your body, get checked and don't worry. If you get sick, then you deal with it and start healing.
This is a timely topic for me too, my breasts are growing super fast and they have been going withiout a pause for a long time now. Next year I should get a cancer screening booked by default as I'm hitting forty years old so that might be easy to deal with without needing to book one myself. Very few cancer cases in my family and zero of them breast cancers so I'm not really worried. Also I got fuckton of moles, few of which are annoying and I would want to get them removed and some might be worthy of checking out that they're not trying to kill me.
Stop worrying, play smart, get checked. Normal healthcare stuff. Also, HRT is a trade off, giving away prostate cancer risk for breast cancer risk, take your pick.