Hi Nannyneet. In answer to your question, I take HRT although my Mum died of breast cancer. I stayed away from it for 10.5 years (apart from a 1 month trial much against my better judgement in peri), but started it 3 years post-meno as my symptoms were still severe and showing no sign of letting up. Prior to this I had been very reluctant due to Mum's illness and had written HRT off as out of the question for me, especially as I had also read that HRT was not advised with migraine, which I also have (transdermal forms are in fact considered OK, just in case you too have migraine).
As I also have other health problems and the menopause symptoms were badly affecting my quality of life, I took advice from a top Endocrinologist I was already seeing for a thyroid disorder & also went to see a well respected Gynae. Both felt HRT was right for me in spite of my family history & the fact I had a long history of benign breast lumps including a lumpectomy. My GP was more cautious & so I took my time and did a lot of research before finally taking the plunge, which my GP then supported with the two consultants' back-up. I am glad I did, although HRT hasn't resolved all my symptoms & has brought other problems that have had to be investigated (persistent bleeding), though on the whole I am better with HRT than without.
I think your risk may depend on the age at which your sister developed breast cancer & perhaps what type it was, so it may be worth getting specialist advice if you are considering HRT. In some cases I think it is possible to have genetic testing, but this carries its own issues in that the result may cause more worry and I think needs careful thought (& perhaps counselling) before going down this path.
I would always recommend anyone to read around and get as much info as possible before taking the decision to start HRT, and this is especially important for ladies like you and I. It's vital for peace of mind to be comfortable with the choice and this can be a very difficult decision. Please don't allow anyone to rush you or pressurise you against your instincts.
I hope you will get plenty of advice about other options you might consider and that you will soon find something to help you feel better.