Part 1: Breast Cancer and Hormone Therapy
“Five minutes of communication can save your life and years’ worth of pain and suffering.” — Robert True, MD
Seems like everyone’s an expert these days regarding your hormones. From your doctors, your hairdresser, or your fitness instructor, conflicting views just mess-up your mind and contribute to a lot of myths and misunderstandings about hormone therapy. Even doctors in different fields or the same fields can’t seem to agree on what’s best for you.
The problem is that confusion in the risks and benefits of hormone therapy is resulting in you not benefiting from this therapy that could not only improve your health but also your quality of life as you grow older. In this series, we will discuss some of the myths and misconceptions about hormone use. You will learn of the risks and benefits of hormone therapy, what the “News” is saying and what the scientific literature is saying. Misunderstandings do happen due to news “hypes”, thus let’s dispel some of these myths and learn the truth so you can reap the benefits and not be afraid of hormone therapy.
MYTH #1: Hormones Cause Breast Cancer
You may be afraid of going on hormone therapy because you believe it might give you breast cancer or at least increase your risk of developing breast cancer. This myth/misunderstanding became very prevalent when a study called the WHI study showed an increase in breast cancer in one group of women in the study.
The study was a very large study of 16,608 postmenopausal women, most of which were over age 60, who used two different regimens of hormone therapy. One group received estrogen alone, the second group received a combo of estrogen plus a synthetic progestin called medroxyprogesterone. The study was supposed to go for around seven years.
At the five-year mark, they checked their data and decided that the combo group had a significant increase in incidence of breast cancer, so they stopped the study for that group. The increase was around 20% increase (8 more breast cancers per 10,000 women years). The news media went wild with this bad news and it was hyped big-time causing a lot of women to stop taking their hormones.
However, the news didn’t say much about the group taking only the estrogen did not show any increased risk. They had 5 less breasts cancers per 10,000 women years. This was good news, but unfortunately the damage and reputation for taking hormones was already tainted. Women right and left got off their hormones from this fear. Unfortunately, they started to suffer from some of the symptoms of menopause plus many started developing osteoporosis since their bones were no longer protected by the estrogen.
The Increased Breast Cancer Risk was due to the Progestin
The reality is that it was not the estrogen (which includes natural estradiol) it was the synthetic progestin that increased the risk of developing breast cancer. Thus, estrogen per se does not cause breast cancer when given alone; i.e. without the progestin. This is the myth that has developed over time and is really a misunderstanding.
A more recent study showed actually the opposite occurs. Many in the WHI continued to take their hormone, particularly estrogen alone. After ten years, the data demonstrated that these women actually developed less breast cancers (24% less) compared to those not taking hormones. Moreover, of those who developed breast cancer they saw a 63% decreased risk of dying from the cancer.
In addition, there was a 39% decrease risk of dying from any cause in the women who continued the estrogen. Of course, the news was quiet regarding this good news and few people heard about this benefit. It proved that estrogen was safe and beneficial when taken long term regarding the incidence of breast cancer. It doesn’t cause breast cancer and may even be somewhat protective.
Estrogen, when given alone thus does not cause breast cancer and may even be protective. With this good news and a plethora of other new information regarding the risks and benefits of hormone therapy, women now have a choice regarding how they want to live their later years. This right to decide on hormone therapy was endorsed in the latest recommendations from the North American Menopause Society. 
Hormone pellet therapy uses estradiol plus testosterone usually. Testosterone may be further protective for breast cancer as demonstrated in other studies, increasing the safety of estradiol therapy even more. Further safety of estradiol is seen when used transdermally (through the skin) – the risks of blood clots and strokes are not increased, which will be discussed in the next part of this series.
Estradiol Alone Doesn’t Increase Breast Cancer
In conclusion, the myth that hormone replacement therapy increases your risks of developing breast cancer can be dispelled if the therapy is performed correctly; i.e. using only natural estradiol hormones without synthetic hormone combinations, such as use with medroxyprogesterone. The decision to use hormone therapy therefore should take this into consideration in addition to all the other many benefits that you will get from this therapy.
 Rossouw JE, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women’s Health Initiative randomized controlled trial. JAMA. 2002 Jul 17; 288(3):321-33. doi:10.1001/jama.288.3.321
 Anderson, et al. “Conjugated equine oestrogen and breast cancer incidence and mortality in postmenopausal women with hysterectomy: extended follow-up of the Women’s Health Initiative randomized placebo-controlled trial” The Lancet Oncology, Vol. 13, No. 5, p476–486, March 7, 2012. http://doi.org/10.1016/S1470-2045(12)70075-X
 Pinkerton JV. Et al. The 2017 Hormone Therapy Position Statement of The North American Menopause Society. Menopause 2017;24:728–53. Epub ahead of print June 20, 2017
 Glaser RL, Dimitrakakis C. Reduced breast cancer incidence in women treated with subcutaneous testosterone, or testosterone with anastrozole: a prospective, observational study. Maturitas. 2013 Dec;76(4):342-9. doi: 10.1016/j.maturitas.2013.08.002