Kathryn Horwitz, PhD, of the Univ. of Colorado Health Science Center, gave a fascinating talk today on "The Year in Hormones and Cancer."
As everyone knows, the WHI showed years ago that HRT increased the risk of breast cancer (though the numbers were small), and that the greatest risk seemed to be for women who were within five years of the start of menopause.
This is "disconcerting," Dr. Horwitz noted, since the effect of HRT on CVD is the opposite-- the further away from the start of menopause one is upon taking HRT, the greater the risk of CV problems.
What to do, then?
That's up to you. But if your patients are gonna use HRT, they should stick to transdermal applications and use the lowest possible dose, since research has found the direct delivery of HRT (as through a skin patch instead of an oral med) may decrease the risk of breast cancer.
And, she advised, don't use HRT at all with breast cancer survivors.
Why? Because research indicates that tumor cells stick around in women who had breast cancer and mastectomies up to 22 years after the mastectomy, even if there are no overt symptoms of the disease.
And-- get this-- one study in which researchers did autopsies on women who did NOT die of breast cancer found that about 10% had evidence of dormant cancerous cells. And 82% of those wouldn't have been detected on a mammogram.
Dr. Horwitz's theory from all this is that HRT doesn't actually cause new cancer cells to develop; instead it activates a reservoir of occult, silent disease cells in some women, and reactivates the dormant cells of breast cancer in others.
The good news is that she thinks this activation can be avoided or mitigated by using local delivery methods of HRT.
And she thinks she'll have a paper out in the next few months to help prove it.