Hormone Receptor (HR) Positive Breast Cancer

Your breast cancer may be “hormone receptor-positive” or HR+. Some breast cancers have receptors on them that attach to the hormones, estrogen, and progesterone, as they circulate in your body. These hormones “feed” the cell and help it grow.

• If your tumor has hormone receptors, it is called hormone receptor-positive or HR+. If your tumor is HR+, the tumor needs estrogen and/or progesterone to grow.
• About 80% of breast cancers are HR+.
• If your tumor does not have hormone receptors, it is hormone receptor-negative or HR-.

Types of Hormone Receptors

• There are two types of receptors, estrogen, and progesterone.
• If your tumor has estrogen receptors, it is called estrogen receptor-positive or ER+.
• If your tumor has progesterone receptors, it is progesterone receptor positive or PR+.
• Your tumor can be positive for one or both hormone receptors. This may be written ER/PR+, ER+/PR-, ER-/PR+.
• HR+ breast cancer can also be HER2 positive.

How can hormone receptors be used to slow cancer growth?

Blocking the action of estrogen and/or progesterone could possibly stop the cancer from growing. There are a few ways in which this can happen:

• Blocking the hormone receptor with another compound prevents the estrogen or progesterone from being able to attach to the receptor and activate the cell.
• Prevent the body from making the hormone: This can be done with medication to block the production of the hormone, or with surgery to remove the organ that makes it. For example, estrogen production can be significantly decreased by surgically removing the ovaries.
• Eliminate the hormone receptors on cells or change their shape: This makes it impossible for the hormone to attach itself to the cell receptor and to activate it, essentially making the hormone unable to function.

How are hormone receptor-positive cancers treated?

HR+ breast cancers can be treated with endocrine therapy (also called hormone therapy) to block the action of hormones. These therapies may be used alone or in combination with chemotherapy, targeted therapy, surgery, and radiation.

• Hormone therapies for HR+ breast cancers include aromatase inhibitors (anastrozole, letrozole, and exemestane), selective estrogen receptor modulators (tamoxifen, and toremifene), and estrogen receptor antagonists (fulvestrant).
• In early-stage breast cancer, hormone therapies may be used along with chemotherapy and targeted therapy such as Herceptin, if the tumor is also HER2 positive.
  • In these cases, hormone therapy may be taken for 5-10 years after completing the initial chemotherapy treatment.
  • In more advanced HR+ breast cancers, hormone therapies are often used in combination with targeted therapies including lapatinib, palbociclib, and ribociclib.
    • You may take one hormone therapy for a while and then it stops working. Your provider may then give you a different hormone therapy.
    • Removing or suppressing (shutting down) the ovaries, puts a pre-menopausal woman into menopause. This shuts down the production of estrogen by the ovaries. Medications used for ovarian suppression are called gonadotropic-releasing hormone analogs, such as goserelin acetate and leuprolide. These medications may be used in combination with other hormone therapies. The ovaries can also be surgically removed in a procedure called an oophorectomy. This can impact fertility, so be sure to talk with your healthcare provider about fertility preservation before starting these therapies.

How can I manage this diagnosis?

• While the diagnosis of breast cancer may be challenging, remember there are many treatment options.
• Learn about your type of breast cancer and common treatments. This can help you ask questions at your oncology visits and feel more in control of your treatment decisions.
• Seek out support groups or peer support (online or by phone).
• All cancers are unique, and you should not compare your experience to others.

Resources

OncoLink's Resources for More Information: Breast Cancer.