Menopause hormone therapy prescribing is an essential skill in the care of women. It is imperative that all prescribers have a science based approach to the benefits and risks of menopause hormone therapy (MHT). In these now forty years of clinical practice as a licensed naturopathic physician and a clinical practice in women’s health, I think I’ve seen every perimenopause/menopause issue, every possible evidence based and historical use natural therapy, and likely every hormone prescription that women have been given (although I still am occasionally surprised……. and alarmed). My alarms especially go off when women are prescribed unusually high doses of estrogen, and inadequate doses of a progestogen if they have a uterus. My alarm is heightened and my concern for her safety is when she has been given a prescription by a practitioner who recently attended a pellet therapy seminar for example. That seminar provided education which then ultimately has the goal of the practitioners being a new and future user of and prescriber of that proprietary method and use of seminar owned medications bought through that company, and lastly but not least, recommending doses of hormones and prescribing patterns that now change the calculation from benefit over risk, to risk over benefit. A classic example I’ve encountered is that practitioners are taught at some seminars, that systemic estrogen therapy can be initiated at any age without risk; or that progesterone cream can be used for endometrial protection when systemic doses of estrogen are given, let alone the high supraphysiologic doses and resulting supra high levels of estrogen that are documented with something like pellet therapy. That’s just one scenario. Don’t get me started on unproven regimens such as the “Wiley Protocol”, or doses of progesterone based on a saliva or urine or serum test result resulting in lower doses of that hormone than given presuming that is then the right dose for her while giving her an estrogen, if she has a uterus, and in fact, this dose is an unproven dose for her estrogen stimulated uterus.
This particular blog addresses estrogen and breast cancer.
Myth: Estrogen causes breast cancer
The primary fear that most women have about menopause hormone therapy (MHT) is that it will cause breast cancer. Not only does most data show that recommended menopausal estrogen doses alone do not cause breast cancer, but even recommended estrogen plus a progestin for 4 years or more appears to increase the risk ever so slightly. Only one extra breast cancer per 1,000 women per year with estrogen and progestin starting at about year 4 of use. Estrogen and bio-identical progesterone, according to three observational French studies, and a recent population based study, does not increase the risk at all. The systemic estrogen alone studies range from 1) a slight decreased risk (the original randomized controlled trial from the Women’s Health Initiative=WHI); 2) slight decreased risk from the 20 year WHI f/u; 3) slight increased risk in the Nurses Health Study; 4) the recent population based study in the next paragraph from the UK; 5) to others with a null effect.
The recent population based case control study of women aged 50 years or older using data from the UK also highlights no increased risk with estrogen alone and different risk dependent on type of progestogen with estrogen as in the 3 observational French studies. Over a course of almost 20 years, there were 43,183 cases of breast cancer identified and matched to 431,830 women in a control group. Compared with women who never used MHT, its use was associated with a very slight increased risk of breast cancer. Compared with never users, estrogens alone were not associated with breast cancer, no matter the type of estrogen. Progestogens appeared to be differentially associated with breast cancer, with micronized bio-identical progesterone having no increased risk and synthetic progestin= 1.28… which translates as this 1 in 1,000 number I mentioned earlier.
While there are many papers that could be sited, the 2022 position statement from the North American Menopause Society (NAMS) provides an excellent summary of the overall issue of MHT and breast cancer, as well as other key issues. (see reference below)
If you want a book that lays out the science in a reliable and evidence based manner, and spares you reading scores of articles, read Estrogen Matters.
So… if you have a need to take systemic and usual standard of care doses of MHT – for moderate to severe hot flashes/nightsweats, or some other perimenopause-menopause symptoms in which MHT might help, or to slow bone loss and prevent osteoporosis, or to possibly reduce the risk of Alzheimer’s Disease and… if you start before the age of 60 or within the first 10 years of menopause, you can feel pretty darn comfortable that the benefits outweigh the risks. One caveat is that there are contraindications to taking systemic MHT and there are preferred methods of delivery and doses. These issues should be addressed with a qualified menopause expert clinician.
References and Resources:
Book: Estrogen Matters: Why Taking Hormones in Menopause Can Improve Women’s Well-Being and Lengthen Their Lives — Without Raising the Risk of Breast Cancer. Avrum Bluming MD, Carol Travis PhD.
“The 2022 Hormone Therapy Position Statement of The North American Menopause Society” Advisory Panel. The 2022 hormone therapy position statement of The North American Menopause Society. Menopause 2022 Jul 1;29(7):767-794.
Abenhaim H, Suissa S, Azoulay L, et al. Menopausal Hormone Therapy Formulation and Breast Cancer Risk. Obstet Gynecol 2022;139(6):1103
Fournier A, Berrino F, Riboli E, et al. Breast cancer risk in relation to different types of hormone replacement therapy in the E3N-EPIC cohort. Int J Cancer; 2005 Apr 10;114(3):448-54.
Fournier A, Berrineo F, Clavel-Chapelin F. Unequal risks for breast cancer associated with different hormone replacement therapies: results from the E3N cohort study. Breast Cancer Res Treat; 2008;107(1):103-111.
Cordina-Duverger, E, Truong T, Anger A, et al. Risk of breast cancer by type of menopausal hormone therapy: a case-control study among post-menopausal women in France. PLoS One; 2013 Nov 1;8(11)
Brinton L, Hoover R, Fraumeni J. Menopausal oestrogens and breast cancer risk: An expanded case-control study. Br J Cancer. 1986;54:825-32.
Armstrong B. Estrogen therapy after the menopause: Boom or bane? Med J Aust. 1988; 148: 213-14.
Dupont W, Page D, Rogers L, et al. Influence of exogenous estrogens, proliferative breast disease, and other variables on breast cancer risk. Cancer. 1989;63:948-57
Palmer J, Rosenberg L, Clark E, et al. Breast cancer risk after estrogen replacement therapy: Results from the Toronto breast cancer study. Am J Epidemiol. 1991;134:1386-95.
Dupont W, Page D. Menopausal estrogen replacement therapy and breast cancer. Arch Intern Med. 1991;151:67-72.
Nachtigall M, Smilen S, Nachtigal R, et al. Incidence of progestin replacement therapy. Obstet Gynecol. 1992;80:827-30.
Colditz G, Hankinson S, Hunter D, et al. The use of estrogens and progestins and the risk of breast cancer in postmenopausal women. NEJM 1995; 332:1589-93.
Willis D, Calle E, Miracle-McMahill H, et al. Estrogen replacement therapy and risk of fatal breast cancer in a prospective cohort of postmenopausal women in the U.S. Cancer xauses Control. 1996;7:449-57.
