discussion of unpublished analysis ) estrogen alone reduces breast cancer risk and does not interfere w/mammographic detection.The take home point for me is that we used the wrong progestin, medroxyprogesterone acetate, rather than bio-identical progesterone (which is available as What's important to note and has remained unchanged is that estrogen plus progestin increases breast cancer risk. Sure, we've developed some nuances, like the fact that estrogen plus progestin's effect on breast cancer may be increased in those starting therapy closer to menopause, is not limited to hormone receptor-positive cancers, interferes w/mammographic detection, and increases breast cancer mortality, all bad things. But we've also learned that (ignoring said Prometrium - and no, I have no financial stake). And in doing so, we've blamed the wrong entity, conjugated equine estrogen (CEE). Don't get me wrong. I'm no big fan of CEE (I'm the doc who advocates transdermal estradiol if you really need MHT). But when you look at the logic, it seems pretty clear to me that if E+P is bad and E alone is fine, the culprit is P, not E. Let's not toss the baby out with the bath water.