That is interesting. My aunt also got breast cancer...about 6 months after starting hormone replacement therapy. This was 10 or so years ago and the doctor told her that the cancer was probably already there, and the hormones just made it grow faster. She had a cyst removed from the same area previously.
We accepted the explanation, and didn't really think any more about it. She wouldn't sue anyone either.
Yeah, I gather the hormones are like fuel to a fire that is already there.