Hormone Therapy FAQs: How Do Hormones Fit Into Breast Cancer Treatment?

PJ Hamel Health Guide February 11, 2008
  • Q. I was diagnosed with DCIS, and have had a lumpectomy and radiation. Now my oncologist says I’ll be doing hormone therapy. I thought women with breast cancer weren’t supposed to do hormone therapy…?

    A. OK, you’re understandably confused. Hormone therapy is different than hormone REPLACEMENT therapy (HRT). HRT has been used for years to treat symptoms of menopause by increasing the level of certain hormones in your body, hormones whose level is dropping as your body slows down with age. HRT is NOT recommended for breast cancer survivors; and healthy women are cautioned about its use, since it’s been shown to raise the risk of breast cancer.

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    Hormone therapy, on the other hand, is using drugs to block the production of hormones in your body, or to block the hormones’ ability to attach themselves to your cells. Certain types of breast cancer rely on hormones to grow. Without the necessary hormones, cancer cells die, and the spread of the disease is stopped.



    Q. Whoa, slow down. Could you tell me what a hormone is?

    A. Sure. We hear about hormones (often “raging hormones”) all our lives, but what are they, exactly? Wikipedia tells us that a hormone “is a chemical messenger that carries a signal from one cell (or group of cells) to another via the blood… In general, hormones regulate the function of their target cells, i.e., cells that express a receptor for the hormone.” Hormones, secreted by your glands (including thyroid, adrenal, et. al.) are involved in almost every biological process, including reproduction, metabolism, growth, and disease protection. Basically, we’d be nowhere without hormones; they keep us alive and functioning. When they’re all in balance, we do fine; when they get out of whack (as they do during menopause), we feel it. Hot flashes, weight gain, sleeplessness, and nasty mood swings are all signs that our female sex hormone levels are dropping.



    Q. Which ones are the “female sex hormones,” and what do they do?

    A. Estrogen and progesterone are the main female sex hormones. They’re called that because they’re present in much greater quantities in females than in males; conversely, testosterone, a male sex hormone, is present in much greater quantities in males than females (although all of us, men and women alike, have at least some of each).

    Estrogen plays a huge role in a number of biological processes. It impacts our ability to bear children, and our weight (by controlling the speed of our metabolism, which is why we gain weight after menopause). It accelerates our growth during adolescence. It helps our circulation, and the elasticity of our skin (which is one reason why, as we grow older and estrogen production slows, we become increasingly wrinkled). It increases our HDL, and decreases our LDL, both of which help our cholesterol level. It even helps us breathe, by keeping the cells in our lungs elastic.

    Progesterone is mainly concerned with reproduction. It regulates our periods, and has a major role in pregnancy, from conception to delivery. Progesterone also helps regulate estrogen; too much estrogen is just as harmful as not enough. (Some wags refer to estrogen as the wild teenager, and progesterone as the calm adult.) And it keeps us flexible (ligaments, joints, skin); helps our blood clot; makes sure our nerves work properly; and pitches in with a number of other body functions.

  • Many of us probably first heard about estrogen and progesterone in relation to birth control pills, which work by pumping synthetic estrogen and synthetic progesterone into your body on a set schedule. Estrogen prevents you from ovulating; no egg, no pregnancy. And progesterone is the backup, making it difficult for sperm and eggs to move, and for a fertilized egg to be implanted in the uterus.

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    Unfortunately, many of us also heard about estrogen and progesterone when our oncologist explained what type of breast cancer we’d been diagnosed with. About 70% of women with breast cancer have a type that grows with the help of estrogen and/or progesterone. Which is actually good news: there are drugs that are known to reduce the recurrence risk of hormone receptor-positive breast cancers. When you take any of these drugs – including tamoxifen, Evista, Arimidex, Femara, Aromasin, Zoladex, and Faslodex – you’re said to be undergoing hormone therapy.