I didn’t have your type of breast cancer but generally the advice about food is simply the same as for any healthy diet. If you have any medications which are incompatible with certain foods, your medical team will make sure you know.
General principles are:
* limit or cut out alcohol and nicotine
* limit or cut out processed meat
* limit sugar
* increase fresh vegetables and eat a wide range of them
* have one of more serves of oily fish a week
* fresh fruit is better than fruit juice - more fibre and possibly less sugar unless freshly squeezed
* eat as varied a diet as possible
Your medical team can advise further. Most supplements are only useful if you are really deficient - it’s worth checking your Vitamin D level and I found additional Vitamin B useful (prescribed by my oncologist) to try and minimise some chemo side effects. It’s sensible to check any supplements with your oncologist. Soy products are sometimes seen as oestrogen high but I’d get advice on that, I suspect you’d have to be eating a lot to make any difference. Everyone will advise you not to google for medical advice, I’d tend to say the same for what to eat.
Your surgery is a great step
forward. This disease is of course worrying but concentrate on enjoying and living the life you have rather than worrying about things that are probably not really relevant. Best wishes.