Estrogen Receptor-Positive Breast Cancer (ER+)

What is ER-positive (ER+) breast cancer?

ER-positive breast cancer (ER+) is a breast cancer subtype. If tests show you have estrogen receptor-positive breast cancer, it means cancerous cells in your breast have high estrogen levels helping them to grow. Checking estrogen receptor levels helps healthcare providers to plan treatment. Healthcare providers treat this condition with surgery and hormone therapy.

This breast cancer subtype is also known as estrogen-positive breast cancer and estrogen receptor-positive breast cancer.

How common is ER-positive breast cancer?

It’s relatively common. About 70% of all breast cancer cases — including men and people assigned male at birth (AMAB) — in the United States are ER-positive.

What are the symptoms of ER+ breast cancer?

People with ER-positive breast cancer typically have common breast cancer symptoms, including:

• A change in the size, shape or contour of your breast.
• A mass or lump, which may feel as small as a pea.
• A lump or thickening in or near your breast or in your underarm that persists through your menstrual cycle.
• A change in the look or feel of the skin on your breast or nipple. Your skin may look dimpled, puckered, scaly or inflamed. It may look red or darker than other parts of your breast.
• A marble-like hardened area under your skin.
• A blood-stained or clear fluid discharge from your nipple.

What causes ER-positive breast cancer?

Cells in your body have hormone receptors. The hormone receptors are a type of protein. Estrogen in your bloodstream can attach to the receptors. This hormone-receptor process is part of typical body function. In healthy cells, estrogen aids normal cell function and growth.

ER-positive breast cancer occurs when estrogen connects with proteins inside cancer cells, causing the cells to grow. It may also happen when estrogen and another hormone, progesterone, connect with proteins inside cancer cells. Breast cancer with high progesterone levels is PR-positive breast cancer.

What are the risk factors?

The overarching risk for women and people assigned female at birth AFAB is long-term exposure to estrogen. Risks for men and people AMAB are linked to situations where they have more estrogen and less testosterone than usual (hormonal imbalance).

Risk factors for women and people AFAB include:

• Having early periods.
• Having late menopause.
• Giving birth later in life.
• Taking hormone therapy for menopause symptoms.

Risk factors for men and people AMAB include:

• Having obesity.
• Having diabetes.
• Having cirrhosis of the liver.

How is ER-positive breast cancer diagnosed?

Your healthcare provider does a breast biopsy to obtain samples of cancer tumor tissue. They send the samples to a lab. There, a medical pathologist tests tissue for signs of hormone receptors. A hormone receptor-positive (HR+) result means estrogen, progesterone or both hormones are fueling cancer growth. If tests don’t find high estrogen levels, the breast cancer is considered estrogen receptor-negative (ER-negative).

What are treatments for ER-positive breast cancer?

Healthcare providers may treat ER-positive breast cancer with:

• Breast cancer surgery to remove tumors.
• Radiation therapy.
• Chemotherapy.
• Hormone therapies like aromatase inhibitors to reduce the amount of estrogen in your body or selective estrogen receptor modulators (SERMS) to reduce the risk that breast cancer will recur (come back).

Treatment side effects

Common chemotherapy and radiation therapy side effects include fatigue, nausea and vomiting. Common hormone therapy side effects may include:

• Joint pain or stiffness.
• Fatigue.
• Weight gain.
• Less or loss of interest in sex.
• Hot flashes.
• Tender or swollen breasts.

If you’re receiving ER-positive breast cancer treatment, ask your healthcare provider about palliative care. This care may help you manage breast cancer symptoms and treatment side effects.

What are ER-positive breast cancer survival rates?

Data from the National Cancer Institute (NCI) show that overall, more than 90% of women and people AFAB were alive five years after diagnosis. NCI data doesn’t break out ER-positive survival rates for men and people AMAB.

When you think about survival rates, it’s important to remember these rates are based on the experiences of large groups of people with the same condition. More than that, these are estimates based on what was going on during a specific time that may be years in the past. If you have questions about survival rates, ask your healthcare provider what you can expect.

Can ER-positive breast cancer come back after treatment?

While this breast cancer type is considered to be less aggressive, there’s a risk of recurrence after treatment, including treatment for early-stage, low-risk ER-positive breast cancer. If you’re concerned that breast cancer will come back, ask your oncologist about your individual risk and what you can do to reduce your risk.

How do I take care of myself?

If you have ER-positive breast cancer, the following suggestions may be helpful:

• Get enough rest. Breast cancer and treatment can be exhausting. Try to remember to rest when you need to, not just when you think you have time.
• Eat well. Treatment may affect your appetite. A diet of fruit, vegetables, lean protein and healthy grains can help you stay strong during treatment.
• Manage your stress. Cancer is stressful. Exercise can help, from regular walks to exercise programs.
• Find support. You’re a breast cancer survivor, starting the day you were diagnosed. Ask your healthcare provider about cancer survivorship programs, which may help you manage some of the challenges of living with breast cancer.

When should I see my healthcare provider?

Contact your provider if your symptoms seem to be getting worse or if you have new symptoms, like pain or weakness in a different part of your body.

What questions should I ask my healthcare provider?

You may want to ask the following questions:

• What treatment do you recommend?
• Will I need to have chemotherapy and radiation or just hormone therapy?
• Will I need hormone therapy for the rest of my life?

Where does ER-positive breast cancer spread?

Breast cancer may spread to people’s lungs, brains, bones and livers. ER-positive breast cancer accounts for about 70% of all breast cancer cases.