Breast Cancer and Hormone Replacement Therapy (HRT)

Perhaps the most significant worry that most women have when considering whether or not to take Hormone Replacement Therapy (HRT) is the possible increased risk of breast cancer. Breast cancer is an estrogen dependent cancer and constitutes approximately 25% of all female cancers, therefore any woman who has an early menopause and does not take any estrogen supplementation will actually reduce her risk of developing breast cancer in later life.

There are two main types of HRT:

  • combination HRT contains the hormones estrogen and progesterone
  • estrogen-only HRT contains only estrogen

Combination HRT increases breast cancer risk by about 75%, even when used for only a short time. Combination HRT also increases the likelihood that the cancer may be found at a more advanced stage, as well as increasing the risk that a woman diagnosed with breast cancer will die from the disease. Breast cancer risk increases the most during the first 2 to 3 years of taking combination HRT. Higher-dose combination HRT increases breast cancer risk more than lower-dose combination HRT. Breast cancer risk goes back down to average about 2 years after you stop taking combination HRT.

Estrogen-only HRT increases the risk of breast cancer, but only when used for more than 10 years. Estrogen-only HRT also can increase the risk of ovarian cancer.

If you’ve been diagnosed with breast cancer or have tested positive for an abnormal breast cancer gene (BRCA1 or BRCA2) and so are at high risk, you shouldn’t use HRT. The hormones in HRT can cause hormone-receptor-positive breast cancers to develop and grow. While only a few small studies have looked at HRT use in women with a personal history of breast cancer, the fact that HRT use increases breast cancer risk among women in general makes almost all doctors advise women with a personal history of breast cancer to avoid HRT. The prescribing sheet included with HRT clearly states that it is “contraindicated in women with a diagnosis of breast cancer.”

Menopausal side effects can dramatically reduce quality of life for some women. These women have to weigh the benefits of HRT against the risks.  If you’re having severe hot flashes or other menopausal side effects and have a personal history of breast cancer, talk to your doctor about non-hormonal options, such as dietary changes, exercise, weight management, acupuncture, or meditation.

The small increase in the incidence of breast cancer in long-term users of HRT should be considered in the context of the benefits of HRT. Long-term use is indicated for the prevention of serious disorders as osteoporosis and cardiovascular disease (and perhaps also useful in the prevention of dementia). Only in women without any risk factor for these diseases and especially for cardiovascular disease, the excess of breast cancer is of real importance in terms of cost-benefit calculations. But for some women a small increase in the incidence of breast cancer is so terrifying, that they accept the probability of an earlier (premature) cardiovascular death.

Whether or not you take HRT, there are also lifestyle choices you can make to keep your breast cancer risk as low as it can be:

  • maintaining a healthy weight
  • exercising regularly
  • limiting alcohol
  • eating nutritious food
  • never smoking (or quitting if you do smoke)

These are just a few of the steps you can take to reduce your risk of breast cancer.

Bottom line: If you’ve been diagnosed with breast cancer or have tested positive for an abnormal breast cancer gene (BRCA1 or BRCA2) and so are at high risk, you shouldn’t use HRT.  Patients with menopausal symptoms should speak to their doctor about treatment options.

(*information for this article was obtained from

About the author: Raja P. Reddy, MD is a board certified diagnostic radiologist specializing in breast imaging. He is also a contributing editor for Digital Mammography Specialists, a leading provider of outpatient women’s imaging services in the greater Atlanta, GA.