I think a healthy diet full of antioxidants ie fruit and veggies, nuts, seeds, fibre, healthy protein etc is beneficial for anyone whether dealing with health challenges or not.
I encourage my kids to "eat the rainbow".
Exercise would also be a wonder drug if it could be patented.
And if you drink alcohol at all, I would consider stopping as there is good research around alcohol and breast cancer, however this is a personal choice and quality of life is also valuable.
Another personal choice is whether to continue hormone therapy whilst having investigations if you haven't actually been diagnosed with anything - the vast majority of lumps and changes flagged by screening mammography turn out to be benign, so do make sure this is your decision as it is a very vulnerable time and women are frequently bullied into stopping beneficial treatment for something that turns out to be benign, and then it can be hard to get it reinstated.