HER2-Positive Breast Cancer

Breast cancer is one of the most common types of cancer, but not all breast cancers are the same. HER2-positive breast cancer is a type of breast cancer that expresses too much of a protein called human epidermal growth factor receptor (HER2). This protein can make cancer cells grow, so HER2-positive breast cancers often spread more quickly than other types. 

Advancements in targeted therapy have made treatment for HER2-positive breast cancer more effective. At Banner MD Anderson Cancer Center, we offer personalized care and access to some of the latest breast cancer treatment options.   

What is HER2-positive breast cancer?

HER2 is a protein that’s on the surface of all breast cells and many breast cancer types contain HER2 proteins. However, in HER2-positive breast cancer, there’s too much of this protein, so breast cancer cells multiply quickly. About 15 to 20% of breast cancers are HER2-positive.

Knowing your HER2 status is important because it guides your treatment plan. This type of cancer may be more aggressive, but specialized treatments that target HER2 can help.

HER2-positive breast cancer risk factors

There are no unique or specific risk factors for HER2-positive breast cancer. However, the following factors may put you at higher risk for many types of breast cancer, including HER2-positive:

• Being female 
• Having had breast cancer before
• Having the BRCA1 or BRCA2 genetic mutation (you can inherit these mutations, but you can’t inherit a bad copy of the HER2 gene)
• Starting your menstrual period early
• Starting menopause late
• Obesity
• Having dense breasts 
• Having atypical ductal hyperplasia
• Taking hormone replacement therapy
• Having more than one alcoholic drink a day
• Having had radiation therapy for certain conditions

Signs and symptoms of HER2-positive breast cancer

Like other types of breast cancer, you may not have symptoms, especially in the early stages. That’s why regular breast cancer screenings are so important.

The symptoms of HER2-positive breast cancer are the same as the symptoms of other types of breast cancer. Be sure to watch for:

• A new lump or mass in the breast (lump may feel hard or have uneven edge)
• Breast swelling or swelling in the armpits
• A change in the size or shape of the breast
• Skin changes, like dimpling, redness or other color changes, creasing or peeling
• Changes in the nipple, such as a nipple that turns inward
• Discharge coming from the nipple other than milk
• Breast pain that doesn’t go away

Diagnosing HER2-positive breast cancer

When you’re diagnosed with breast cancer, your health care provider will remove part of the tumor (biopsy) to examine it in a lab. According to the American Cancer Society, all invasive breast cancers should be tested for levels of HER2. Tests include:

• Immunohistochemistry (IHC): This test looks at the amount of HER2 protein on the cancer cells. Results are scored from 0 to 3. Scores of 0 or 1 are negative, 2 is borderline or equivocal and 3 is HER2 positive.
• Fluorescence in situ hybridization (FISH): This test measures the number of HER2 genes in the cancer cells. It’s usually done if the IHC test result is 2 (borderline/equivocal).

These tests help your provider create a treatment plan tailored to your needs.

Stages of HER2-positive breast cancer

Like other breast cancers, HER2-positive breast cancer is classified into stages based on the size of the tumor and whether the cancer has spread to the lymph nodes or other parts of the body. Stages range from stage 0 (non-invasive) to stage 4 (metastatic).

HER2-positive breast cancer tends to spread to the bones, brain, liver, lungs and skin.

Treatment for HER2-positive breast cancer

At Banner MD Anderson, we use evidence-based treatments for HER2-positive breast cancer. Your treatment plan may include:

• Targeted therapy: HER2-targeted drugs are designed to attack cancer cells. These therapies have revolutionized the treatment of HER2-positive breast cancer and are a standard part of care. Common options include:
  • T-DXd (Enhertu), an antibody-drug conjugate (targeted therapy and chemotherapy combined) that attaches itself to the HER2 proteins on the cancer cells to stop the cancer from growing
  • Trastuzumab (Herceptin), which blocks HER2 receptors to stop cancer growth
  • Pertuzumab (Perjeta), which is often given with trastuzumab to make treatment more effective
  • T-DM1 (Kadcyla), which is a combination of trastuzumab and chemotherapy that delivers the chemo directly to cancer cells
  • Kinase inhibitors such as lapatinib (Tykerb), neratinib (Nerlynx) or tucatanib (Tukysa)
• Chemotherapy: Chemotherapy combined with targeted therapy for HER2-positive breast cancer, such as trastuzumab (Herceptin), pertuzumab (Perjeta) or margetuximab (Margenza), may make treatment more effective. Chemotherapy can help shrink the tumor before surgery or eliminate cancer cells that may have spread. 
• Surgery options may include:
  • Lumpectomy: Removing the tumor and a small margin of surrounding tissue
  • Mastectomy: Removing the entire breast
  • Breast reconstruction: Either at the same time or later
  • Lymph node removal: To see if the cancer has spread to the lymph nodes
• Radiation therapy: This treatment may eliminate any remaining cancer cells in the breast or nearby lymph nodes. It’s often used after a lumpectomy or if cancer cells are detected in the lymph nodes.
• Hormone therapy: Hormone therapy may block hormones that make cancer grow. It’s used if cancer is hormone receptor-positive as well as HER2-positive.
• Clinical trials: Trials can give you access to cutting-edge treatments that are not yet widely available. Ask your provider if participating in a clinical trial at Banner MD Anderson is a good option for you.

If you have a tumor that’s two centimeters (about three-quarters of an inch) or less, your provider may recommend surgery first, followed by chemotherapy and targeted therapy.

If your tumor is bigger than two centimeters or has spread to nearby lymph nodes, you will probably have chemotherapy and targeted therapy first, followed by surgery.

Living with HER2-positive breast cancer

Coping with a breast cancer diagnosis can be overwhelming but support can help. At Banner MD Anderson, our approach to care includes counseling and support groups so you can manage the emotional impact and connect with others who understand what you’re going through.

Part of living with cancer means managing side effects. Treatments like targeted therapy and chemotherapy may cause fatigue, nausea or hair loss. Tell your care team about any side effects so they can help you manage or reduce them.

Getting care

When you choose Banner MD Anderson for HER2-positive breast cancer care, you’ll get the best possible care every step of the way. You’ll have access to:

• Our team of specialists who create a treatment plan that’s right for you
• The latest techniques to diagnose and treat breast cancer
• Clinical trials that offer effective treatments
• Therapies and support for your physical and emotional health

From diagnosis to recovery, you can rely on Banner MD Anderson for leading-edge care and unwavering support. 

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