This comment is from the Food & Health Skeptic. You can find the abstract etc there.
It's been known for years but there are any number of statements to the contrary. The presentation of the findings below is, however, very misleading, as usual. They only discuss relative risk, not what most people want to know: absolute risk. What they don't tell you (but which any calculator will) is that out of the big group of old ladies studied over a 10 year period, only 5% got cancer, so the risk for ALL groups was small. Most of the variations on HRT use would move you, for instance, from being around 3% at risk to 4% at risk -- which trivial change is in line with what has previously been reported