Hormone Receptor-Positive Breast Cancer: What It Is + How It’s Treated
This is the most common type of breast cancer.
Breast cancers can be categorized in a number of ways, one of which being receptor status. This refers to certain proteins on the surface of cells that “receive” things (such as hormones) to fuel the growth of the cancer.
“Think of [receptors] as little baseball mitts that sit on the surface of the cell,” says Amy Tiersten, MD, hematologist and oncologist at Mount Sinai Hospital in New York City. There are three types of receptors that could potentially be on a breast cancer cell: estrogen, progesterone, and HER2/neu.
What Is Hormone Receptor-Positive Breast Cancer?
If breast cancer cells have either many estrogen or many progesterone receptors, this is categorized as hormone receptor-positive breast cancer. This means that the breast cancer is being fueled by either estrogen (ER-positive) or progesterone (PR-positive)—or in many cases, both.
If the cancer cells have neither receptor, this is known as hormone receptor-negative. This might mean they have an overexpression of the HER2/neu protein instead (HER2-positive breast cancer) or they have none of the receptors (triple-negative breast cancer).
Here’s why doctors care about receptor status: Many of the treatments for breast cancer are catered toward the receptor status, so knowing what your receptor status is can help you and your doctor find the most effective treatment for your specific subtype of breast cancer.
Learn more about the different subtypes of breast cancer receptor status here.
Treatments for Hormone Receptor-Positive Breast Cancer
The mainstay of treatment for hormone receptor-positive breast cancer is anti-estrogen medications. There are different types that inhibit the effect of hormones on the cancer cell in various ways.
For example, one type of hormone therapy for breast cancer “blocks the cell’s estrogen receptor from interacting with whatever estrogen is in a woman’s body,” while another kind “actually lowers the amount of estrogen in the person’s body and starves these cells that are dependent upon estrogen to live,” says Dr. Tiersten.
A newer category of drugs that is effective against hormone receptor-positive breast cancer is CDK4/6 inhibitors, which are commonly used for more advanced, metastatic breast cancers. They are used in combination with anti-estrogen therapy and can prolong the effectiveness of the treatment, in order to keep the disease from progressing.
Find out more about how different subtypes of breast cancer are treated here.
Dr. Tiersten is a professor of medicine, hematology, and medical oncology at the Icahn School of Medicine at Mount Sinai. She sees patients at the Dubin Breast Center.
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Breast cancers that express either the estrogen receptor
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or the progesterone receptor on the surface of the cell
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are considered hormone receptor-positive breast cancers.
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That's very important because the role of anti-estrogen medications
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plays a very big role in the treatment of that type of breast cancer.
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There are several different subtypes of breast cancer
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and that is dictated by which receptors
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are on the surface of the breast cancer cell.
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So there are three possible receptors.
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Receptors, think of them as like little basemall mitts
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that sit on the surface of the cell.
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There's the estrogen receptor, the progesterone receptor,
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and then there's a protein called HER2/neu.
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The hormone receptor-positive type, the cancers that have those receptors,
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can respond to anti-estrogen medications.
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About 25 percent of breast cancers overexpress the HER2 protein.
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Those are considered HER2-postiive breast cancers,
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and it's an important thing to know because there are certain targeted therapies
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toward the HER2 receptor.
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The anti-estrogens are really the most effective
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and important part of the treatment.
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They're really the mainstay of treatment,
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and chemotherapy's sort of more icing on the cake in that setting.
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So there are certain anti-estrogen medications,
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such as tamoxifen, which is a drug that blocks the cell's estrogen receptor
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from interacting with whatever estrogen is in a woman's body.
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The aromatase inhibitors are a different form of anti-estrogen medication
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that actually lower the amount of estrogen in the person's body
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and starves these cells that are dependent upon estrogen to live.
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There are other forms of anti-estrogen medications
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that are used in more advanced hormone receptor-positive breast cancer,
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and there are new categories of drugs called CDK4/6 inhibitors,
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which appear to prolong the amount of time that a woman would respond
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to a particular anti-estrogen medication.
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Those drugs that appear to prolong the cell's sensitivity
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to anti-estrogen medications are now being studied
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for earlier stage breast cancer that's hormone receptor-positive.
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Breast cancer HER2 status. Atlanta, GA: American Cancer Society, 2019. (Accessed on March 13, 2022 at https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/breast-cancer-her2-status.html.)
Breast cancer hormone receptor status. Atlanta, GA: American Cancer Society, 2019. (Accessed on Macrh 13, 2o22 at https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/breast-cancer-hormone-receptor-status.html.)
CDK4/6 inhibitors for treatment of metastatic breast cancer. Susan G. Komen. (Accessed on March13, 2022 at https://ww5.komen.org/BreastCancer/CDK46inhibitorsfortreatmentofmetastaticbreastcancer.html.)