Estrogen Receptor, Progesterone Receptor Tests

Estrogen Receptor, Progesterone Receptor Tests
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What are estrogen receptor/progesterone receptor (ER/PR) tests?

Estrogen receptor/progesterone receptor (ER/PR) tests are used to help guide breast cancer treatment. Receptors are proteins that attach to certain substances. ER/PR tests look for receptors that attach to the hormones estrogen and progesterone in a sample of breast cancer tissue. Estrogen and progesterone play key roles in a woman’s sexual development and reproductive functions. Men also have these hormones, but in much smaller amounts.

About 70 percent of all breast cancers in women have receptors that attach to estrogen and/or progesterone. About 80 percent to 90 percent of breast cancers in men have these receptors. Breast cancers with estrogen and/or progesterone receptors include the following types:

  • ER-positive (ER+): Cancers that have estrogen receptors (ER)
  • PR-positive (PR+): Cancers that have progesterone receptors (PR)
  • Hormone receptor-positive (HR+): Cancers that have one or both types of these receptors.

Breast cancers without ER or PR receptors are known as HR-negative (HR-).

ER/PR tests will show whether there are ER and/or PR receptors on your breast cancer cells. Test results are frequently referred to as the hormone receptor status. If your hormone receptor status shows you have one or both of these receptors on your cancer cells, you may respond well to certain types of treatments.

Other names: ER/PR IHC testing, hormone receptor status

What are they used for?

ER/PR tests are used to guide treatment for breast cancer patients.

Why do I need an ER/PR test?

You may need this test if you’ve been diagnosed with breast cancer. Knowing your hormone receptor status will help your health care provider decide how to treat it. If you have ER-positive, PR-positive, or HR-positive cancer, drugs that lower hormone levels or stop the hormones from fueling cancer growth can be very effective. If you have HR-negative cancer, these types of drugs won’t work for you.

What happens during ER/PR testing?

Your provider will need to take a sample of breast tissue in a procedure called a breast biopsy. There are three main types of breast biopsies:

  • Fine needle aspiration biopsy, which uses a very thin needle to remove a sample of breast cells or fluid
  • Core needle biopsy, which uses a larger needle to remove a sample
  • Surgical biopsy, which removes a sample in a minor, outpatient procedure

Fine needle aspiration and core needle biopsies usually include the following steps:

  • You will lay on your side or sit on an exam table.
  • A health care provider will clean the biopsy site and inject it with an anesthetic, so you won’t feel any pain during the procedure.
  • Once the area is numb, the provider will insert either a fine aspiration needle or core biopsy needle into the biopsy site and remove a sample of tissue or fluid.
  • You may feel a little pressure when the sample is withdrawn.
  • Pressure will be applied to the biopsy site until the bleeding stops.
  • Your provider will apply a sterile bandage at the biopsy site.

In a surgical biopsy, a surgeon will make a small cut in your skin to remove all or part of a breast lump. A surgical biopsy is sometimes done if the lump can’t be reached with a needle biopsy. Surgical biopsies usually include the following steps.

  • You will lie on an operating table. An IV (intravenous line) may be placed in your arm or hand.
  • You may be given medicine, called a sedative, to help you relax.
  • You will be given local or general anesthesia, so you won’t feel pain during the procedure.
    • For local anesthesia, a health care provider will inject the biopsy site with medicine to numb the area.
    • For general anesthesia, a specialist called an anesthesiologist will give you medicine so you will be unconscious during the procedure.

    Will I need to do anything to prepare for the test?

    You won’t need any special preparations if you are getting local anesthesia (numbing of the biopsy site). If you are getting general anesthesia, you will probably need to fast (not eat or drink) for several hours before surgery. Your surgeon will give you more specific instructions. Also, if you are getting a sedative or general anesthesia, be sure to arrange for someone to drive you home. You may be groggy and confused after you wake up from the procedure.

    Are there any risks to the test?

    You may have a little bruising or bleeding at the biopsy site. Sometimes the site gets infected. If that happens, you will be treated with antibiotics. A surgical biopsy may cause some additional pain and discomfort. Your health care provider may recommend or prescribe medicine to help you feel better.

    What do the results mean?

    The results will show whether you have a hormone receptor-positive or negative type of cancer. If your hormone receptor status is positive, the test also shows the levels of estrogen and/or progesterone receptors. The higher the levels of receptors, the more effective certain medicines may be in treating your cancer. If your hormone receptor status is negative, these medicines will not be effective.

    If you have questions about your results, talk to your health care provider.

    Is there anything else I need to know about ER/PR tests?

    HER2 testing is often done at the same time as ER/PR testing. That is because some hormone receptor cancers are also HER2-positive. HER2 is a protein found on the surface of all breast cells. Treatments for HER2-positive breast cancer can be very effective but are not effective for HER2-negative cancers.

    Courtesy of MedlinePlus from the National Library of Medicine.