The confusion around hormone replacement therapy (HRT) and the risk for breast cancer continues to grow. Women should know that they are not the only ones confused and frustrated every time a new study is reported. Doctors and health practitioners are also uncertain in what is safe and appropriate for their patients.
Many doctors have just stopped recommending hormones to women while others only feel comfortable prescribing HRT if a woman signs a consent releasing the physician from any litigation processes if the woman develops breast cancer.
As this newest study is presented, please take into consideration that this British study did not come from a randomized trial, but was an observational study. There are very distinct differences in these types of studies.
In randomized trials, people are chosen randomly to either take a medication or a placebo and are then studied over time. In an observational study, those in the study make their own choices on whether to take the medication or not. In this case, there can be differences between people who take HRT and those who do not, and the difference between those two types of women (not just the drugs) may influence the study outcomes.
The other limitation of the study was the type of hormones used. The rate of breast cancer was higher in those taking the most commonly used hormones, estrogen combined with progestin. The study did not give the actual names of the hormones used, but is most likely Prempro, the same hormone combination that was used in the Women’s Health Initiative Study from 2002. The highest incidence of breast cancer were in women (ages 50-59)who started these hormones less than 5 years after menopause began. There was less of a risk in women starting these hormones later.
Among users of estrogen-only hormonal therapy, there was little or no increase in the risk of breast cancer among women who started hormonal therapy 5 years or more after menopause.
Women who take estrogen without progesterone, are those who have had a hysterectomy.
There were even some studies published in The Journal of the American Medical Association in 2004 and 2006 showing statistical meaningful data that taking estrogen significantly LOWERED the risk of breast cancer in certain women.
This is all quite confusing. So is the increased risk of breast cancer due to the combination of estrogen and progestin, or the fact that this form of HRT is synthetic? Does it matter if these hormones are taken orally or transdermaly (on the skin)? We know that some progestogens (such as medroxyprogesterone acetate) antagonize the beneficial effects of estrogens and that the exposure of breast tissue to these circulating synthetic progestogens increase breast density.
The Women’s Health Initiative randomized trial of 2002 indicated that starting hormones earlier within 5 years from when menopause started benefited women against heart disease. It also favored towards transdermal estrogen verses oral.
So we may find that there’s a trade off depending on when HRT is taken in reference to the start of your period, between the risk of breast cancer and heart disease.
More studies need to be done regarding the use of bio-identical hormones and their relationship between when they should be started and whether the risks and benefits are similar to other hormones. I do agree with using HRT for the shortest period of time and the lowest dose.
This is when individualizing HRT and its use with each woman is so important. Risk for heart disease, breast cancer, osteoporosis, and colorectal cancer needs to be discussed with your practitioner. Women should not be afraid to use hormones. It may benefit some women irregardless of when they start it.
References: Beral, V, Reeves, G, et al. Breast Cancer Risk in Relation to the Interval between menopause and Starting Hormone Therapy. J National Cancer Institute, 2011; 103: 296-305.