Finally, authors who are willing to look at the “good news” results from the WHI and to look at the hormone that is actually causing the increase in breast cancer – it’s the progestin, not the estrogen. As the authors state this is old news, in the WHI it was clearly shown that women who took estrogen only did have a decreased risk of breast cancer. Even though as the authors state that overall the reduction did not reach clinical significance, the message that is important is that estrogen alone did not INCREASE the risk of breast cancer. The only group that showed an increased risk of breast cancer was the group where estrogens were combined with progestin (an artificial form of progesterone).
It is even more interesting when you combine this data with other data coming out of the EPIC/E3N cohort in France. This is a study in which over 100,000 women have participated for over 8 years and has shown that in women who take estradiol with natural progesterone the risk of breast cancer is even lower than in women who take estrogens alone. In this study they compared this group with women who take estrogen combined with medroxyprogesterone acetate, the same progestin given in WHI. In both the WHI study and the EPIC study, the combination of estrogen with progestin was shown to significantly increase breast cancer risk whereas estrogen plus natural progesterone decreased the risk of breast cancer.
This data has demonstrated repeatedly that estrogens given with progesterone are a safe form of hormone replacement therapy that can be used to treat the symptoms of menopause, maintain bone health, decrease the risk of colon cancer and decrease the risk of heart and Alzheimer’s disease. The most important factor remains the choice of hormones used and these should be prescribed by a doctor who is familiar with these studies and is an expert in the field of hormone replacement therapy.
Read the BusinessWeek article here: Estrogen-Only Hormone Therapy May Reduce Breast Cancer Risk for Some
-Jennifer Landa, M.D.
Chief Medical Officer, BodyLogicMD