Does Hormone Therapy Use After Menopause Increase Risk of Breast Cancer Diagnosis?

Does Hormone Therapy Use After Menopause Increase Risk of Breast Cancer Diagnosis? Does Hormone Therapy Use After Menopause Increase Risk of Breast Cancer Diagnosis?

By: Holly Pederson, MDErika Klempay, PA-C • Posted on October 11, 2019

In a recent study published by The Lancet, the results suggested that women who use hormone therapy after menopause are at an increased risk for breast cancer diagnosis. The study used combined data from 58 different studies and looked at women who took estrogen alone and estrogen plus a progestogen, and then compared their risk to women who did not take any medication. Progestogens/progesterone are necessary to prevent uterine cancer if a woman is on estrogen. If she does not have a uterus, she can take estrogen alone.

What Risks Did The Study Show?

The study showed that the risk for breast cancer was greater for:

  • Women who took combined therapy-estrogen/progesterone rather than estrogen alone
  • Women who are currently taking hormone therapy rather than past users
  • Women who have used hormone therapy for a long duration of time.

Importantly, there was NO excess risk seen with women who have used vaginal estrogen.

The risk persisted for more than 10 years after stopping hormone therapy (HT). However, these risks were VERY SMALL.


Roughly 6,000 women in the U.S. transition into menopause each day. For many women, this means experiencing hot flashes, night sweats, vaginal dryness and having difficulty sleeping, which can ultimately contribute to a decreased quality of life. Hormone therapy has been proven to be THE most effective treatment for vasomotor symptoms of menopause, while also decreasing the risk of postmenopausal bone loss and fractures. Postmenopausal women are also at an increased risk for cardiovascular disease, bone loss, and cognitive decline. One can argue that a woman's overall well-being can be considerably affected by over generalization and misinterpretation of this data. For postmenopausal women, the decision to initiate hormone therapy should be individualized, weighing the pros and cons. A VERY SMALL INCREASED RISK FOR BREAST CANCER diagnosis (NOT death) possibly related to hormone therapy is only one part of the discussion of risks and benefits.


An average 50 year old woman has a 1.3% risk of developing breast cancer over the next 5 years. Using this data, if she takes combined hormone therapy, her risk over the next 5 years goes up to 2%, STILL VERY LOW (and even lower if she takes estrogen alone.) MANY women would choose to accept this risk given the benefits of hormone therapy. It is very easy for this data to be exaggerated and instill fear in women who are suffering. The absolute risks of hormone replacement in the 50-60 year old age group, including that for breast cancer, are very low. Fifty years of research into hormones has not shown any increase risk of mortality from hormone therapy and several randomized controlled studies show a DECREASED risk of death in women who take hormone therapy


We also need to remember to optimize the factors that we can to reduce breast cancer risk! Many women don't realize that lifestyle factors affect breast cancer risk.

Know your family history. Twelve percent of breast cancers can be genetic. High risk women need more intensive evaluation. All women, regardless of family history should pursue a healthy lifestyle.

  • Maintain an ideal body weight. Weight gain of 30 lbs in midlife increases risk of breast cancer diagnosis more than menopausal HT.
  • Limit alcohol consumption to less than 5 drinks per week and if you drink alcohol be sure to ingest enough folic acid 0.4 mg daily.
  • Exercise daily.
  • Treat any vitamin D deficiency .

Take charge, be healthy, know your risks and make your own decisions with the help of your doctor!

Be Strong, Be Healthy, Be in Charge!

- Holly J. Pederson, MD and Erika Klempay, PA-C

About Holly Pederson, MD

Holly Pederson, MD is the Director of the Medical Breast Program at Cleveland Clinic and Associate Professor of Medicine at CCLCM. She completed a clinical genetics fellowship at CCF in 2008 and the City of Hope Course in 2017. She is actively involved in clinical research and is co-appointed in the Lerner Research Institute.

She has served on the NCCN Risk Reduction and Genetic Committees and speaks nationally with a focus on management of high-risk patients. She has developed an internal fellowship for training of Medical Breast Providers, a program which she helped to create.

About Erika Klempay, PA-C

Erika Klempay, PA-C is a Provider in the Medical Breast Services at Cleveland Clinic. Her practice focuses on breast cancer risk assessment, management of the high risk patient, breast diagnostics, and survivorship care.

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