This is an old thread and I can attest, based on a LCIS Facebook group, that all women are getting lifetime risks that are all over the place. Some physicians still use the T-C calculator (also available online), when more enlightened docs say those tools over estimate the lifetime risk of BC when you've been dx'd with LCIS. The over inflate the numbers. And yet some docs still use it? I was diagnosed at 65. I was told by MSK that my lifetime risk was 20-25%. But I heard from others that MSK doesn't really like to give a percentage. Because they simply don't really know, I imagine. Yes, if you've had family history (I don't), test postive for one or more of the 25-40 odd genes that may contribute to the development of BC (I tested negative), then of course. Your risk will be higher.
They still say "most" women will not go on to get BC if diagnosed with LCIS. So confusing.

I sincerely hope that artificial intelligence will help with all this. That it will do a more accurate job of reading and predicting BC risk from scans, and will be able to spot lesions that should be left alone - so few or no false positives which are miserable to go through.