I believe there is some suggestion in the data that, though estrogen users, more the women who use estrogen replacement therapy rather than contraceptives have an increased risk of breast cancer, they may actually have a lesser mortality because they are more likely to be monitored with regular mammograms and have an earlier diagnosis. Again, the final answer awaits.
Well, I sure have been getting lots of chances to be monitored with regular mammograms the past five years, since my breast cancer was detected and treated. No history of breast cancer in my family, but 7 or 8 years on HRT first to "get me through the hot flashes" and then later because I had "a history of cardiovascular problems in the family." What they "forgot" to tell me was that whenever I finally did decide to stop the HRT, I would get to experience the hot flashes anyway, even if I was 75 or 80 when I did so!
There are some big studies going on about pros and cons of HRT. It appears all that much vaunted heart protection and bone protection go the way of the dodo bird soon after HRT is discontinued, anyway. Now, do I think HRT "caused" my breast cancer? Well, yes and no. One of the doctors of the Women's Health Initiative's huge 70,000+ woman study told my group that there was no apparent cause of cancer by the HRT. No relationship at 1 year or 2, even 3, 4, 5, or 6. Then, interestingly, his graph showed that about 7 or 8 years into the use of HRT, there was a dramatic rise in the correlation between breast cancer and HRT. Just a coincidence, I suppose? However, Dr. Susan Love's Breast Book describes the progression of a cancer cell from its first mutation. Many just "go away," probably destroyed by the body's immunue system. However...estrogen feeds many breast cancer cells and fans them into growth, like feeding oxygen to a fire. Care to guess how many years it takes that single cancer cell to grow large enough to be detected? Six or seven years. Remember the point when the correlation between HRT use and breast cancer shows up many times higher than it was at year 1 or 2?
HRT may not have "caused" my cancer, (caused that first mutation) but there is not the slightest doubt in my mind that it encouraged it to grow into an invasive tumor that would have taken my life (and still might) had it not been discovered, and that the mutant cell might never have done so without it. Yes, I got the hot flashes when I stopped the Premarin -- with a vengeance. Would I have taken Premarin then, if I had known then what I know now? Not on your tintype.