Hormone Replacement Therapy vs. Hormone Therapy: What's the Difference?

Patient Expert

Women are often confused by two types of hormone therapy they might encounter. The two have radically different goals – and one can be dangerous to your health, especially if you're a breast cancer survivor.

If you're a breast cancer newbie (or have never been through treatment), your only experience with hormones may be way back in puberty, when the wild swings of newly active female hormones made you crazy. Or perhaps you've been through menopause, suffered through the decline of those same hormone levels – and were prescribed a continuing course of hormone replacement therapy (HRT) by your general practitioner.

HRT involves taking drugs that raise your estrogen and progesterone levels – if not back to their pre-menopause norm, at least to something approaching that. The result? All kinds of potential positives, including stronger bones, shinier hair, a better mood, sharper memory, and healthier skin.

If you've been through breast cancer treatment, you've no doubt discussed hormone therapy with your oncologist. Not hormone REPLACEMENT therapy, but hormone therapy: drugs to suppress estrogen and progesterone.

About 80 to 85 percent of women with breast cancer have a type of cancer that needs estrogen and/or progesterone to grow; thus preventing the cancer from obtaining those hormones is a solid, proven way to discourage a recurrence. Survivors take a daily pill – tamoxifen, Arimidex, Femara, or Aromasin – for up to 10 years or more after the end of active treatment. The drug prevents cancer from growing by lowering hormone levels drastically; or by preventing cancer cells from bonding with those hormones.

See the difference? Breast cancer survivors take hormone therapy to stay alive. Those without breast cancer take hormone replacement therapy to deal with menopausal side effects.

So what if you're a breast cancer survivor undergoing menopause?  Can you take HRT to deal with those darned hot flashes and memory lapses?

Not a good idea, in most cases. Think about it: HRT increases your circulating estrogen and progesterone. Your cancer needs these hormones to thrive. Why make it easy for hungry cancer cells by loading the table with an abundance of "food"?

One exception: If you're among the 15 to 20 percent of women who've been diagnosed with triple negative breast cancer (TNBC), your cancer doesn't rely on hormones to grow. So, working with your oncologist, it may be possible for you to take a short-time, limited amount of HRT, if your menopausal symptoms are particularly difficult.

Why the cautionary note? Studies show that HRT increases a woman's risk of breast cancer. So even though you've been diagnosed with a triple-negative cancer, it's possible to be diagnosed with a second, new cancer; and it might not be TNBC.

Attention, all of you healthy women out there currently taking HRT, or considering it: be sure to weigh its obvious benefits against its possible deadly risk. Discuss with your doctor your own breast cancer risk, based on family history and other factors. If your risk is low, you might very well take a chance with HRT. But if it's already higher than normal, you'll want to think hard about opening the door to breast cancer.

See more helpful articles about HRT for menopausal side effects:

HRT: Good, Bad, Good… Now Bad Again?

Cooling Down Hot Flashes: Is HRT Safe for You?

Breast Cancer and Hormone Replacement Therapy

Weigh the Risks and Benefits of Hormone Replacement Therapy

See more helpful articles about hormone therapy to prevent breast cancer recurrence:

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

Hormone Drugs and Bone Loss: Beware Hidden Damage

Hormone Therapy for Metastatic Breast Cancer: Faslodex FAQS

Tamoxifen FAQS

Arimidex, Aromasin and Femara FAQS

Breast cancer survivor and award-winning author PJ Hamel, a long-time contributor to the HealthCentral community, counsels women with breast cancer through the volunteer program at her local hospital. She founded and manages a large and active online survivor support network.