Hormone Receptor-Positive Breast Cancer

When breast cancer is hormone receptor positive (HR+), it means the cancer cells have receptors on them that attach to certain hormones in your body. This matters because cancer cells with hormone receptors may attach to those hormones to grow.

HR-positive breast cancer grows more slowly than hormone receptor-negative breast cancer because it needs to complete this extra step. And if you can prevent the cancer cells from binding to these hormones, you can prevent the cancer from growing.

Types of HR-positive breast cancer

Hormone receptor-positive breast cancer may bind to estrogen, progesterone or both. Types include:

• Estrogen receptor-positive breast cancer (ER+): This means the cancer has receptors that bind to estrogen. Most breast cancers (at least two-thirds) are ER+.
• Estrogen receptor- and progesterone receptor-positive breast cancer (ER/PR+): This type binds to both estrogen and progesterone. More than half of breast cancers are ER/PR+.
• Progesterone receptor-positive breast cancer (PR+): This type has receptors that bind to progesterone, but not estrogen. It’s the least common type. 

Symptoms of hormone receptor-positive breast cancer

Hormone receptor-positive breast cancer doesn’t cause different symptoms from hormone-negative breast cancer. Testing the cancerous tissue is the only way to tell if your breast cancer is hormone receptor positive. General breast cancer symptoms include:

• A breast lump that you can see or feel
• A change in the size or shape of your breast
• A change in the look or feel of the skin on your breast
• Discharge from your nipple
• Swelling or thickening in your armpit
• Breast pain

Why is some breast cancer hormone receptor positive?

Breast cancer cells may have hormone receptors because normal breast cells do. Normal cells in your breast tissue respond to hormones by growing or changing, especially during female reproductive cycles. And breast cancer cells are abnormal breast cells.

While the hormones estrogen and progesterone play a larger role in female anatomy, they also exist in smaller amounts in males. This is why male breast cancer can also be hormone receptor-positive. (You only need 1% of cancer cells with hormone receptors to be HR+.)

But having more of these hormones may raise your risk. Cancers that depend on estrogen to grow are more likely to occur when you have more estrogen in your body. Things like hormone replacement therapy, pregnancy and obesity can raise your estrogen and your risk.

How doctors diagnose HR-positive breast cancer

To test breast cancer for hormone receptors, your healthcare provider must first take a sample of the cancer. This is called a biopsy. They’ll send the sample to a lab for testing. The lab will do an immunohistochemistry test (IHC test) to look for hormone receptors.

An IHC test checks for important proteins in cancer cells. Hormone receptors are one type of protein it looks for. Others include HER2 and KI-67. Your pathology report will tell you whether the cancer you have is positive or negative for any of these proteins. 

How is hormone receptor-positive breast cancer treated?

Having hormone receptor-positive breast cancer means your provider can treat it with hormone therapy (endocrine therapy). This is a category of cancer treatment that works by blocking the hormones that the cancer needs to bind to in order to grow.

Hormone therapy for breast cancer includes several types of medications that work in different ways: 

• Aromatase inhibitors suppress estrogen by blocking the enzyme aromatase, which turns other hormones into estrogen.
• Estrogen receptor antagonists work by binding to estrogen receptors, preventing estrogen from binding to them.
• Ovary suppressants (GnRH agonists) slow cancer growth by preventing your ovaries from making estrogen.
• Selective estrogen receptor modulators (SERM) block estrogen from connecting with breast cancer cells.

Surgery is another form of hormone therapy for cancer. In some cases, your provider might recommend removing your ovaries to manage estrogen levels. 

The types of hormone therapy your provider recommends will depend on the type of breast cancer you have, the stage and how it responds. Your personalized treatment plan will likely also include other common breast cancer treatments, like:

• Breast surgery (either a lumpectomy or mastectomy)
• Chemotherapy
• Radiation therapy
• Targeted therapy

What can I expect if I have hormone receptor-positive breast cancer?

In general, hormone receptor-positive breast cancer has a better prognosis (outlook) than hormone receptor-negative breast cancer. That’s because hormone therapy offers ways to slow the cancer down. The more treatment options you have, the better your prognosis is.

You can successfully treat hormone receptor-positive breast cancer. But many different factors can influence your prognosis, including the cancer type and stage. Your healthcare provider is the best person to ask about what you should expect from treatment.

Can your hormone receptor status change?

Yes, it can. Sometimes, breast cancer that previously had no hormone receptors develops some over time. And others, breast cancer that was previously hormone receptor-positive loses its receptors over time. Changes occur in an estimated one-third of cases.

If your breast cancer progresses — or comes back after going away (recurrence) — your provider might want to test it again. Changes to your hormone receptor status will affect your treatment plan going forward, and maybe your outlook.