About 20 percent of people with breast cancer have HER2-positive tumors. As scientists continue to learn more about the significance of HER2 status, new and more effective treatments have become available to target HER2-positive breast cancer cells. These advances have improved outcomes for many people with this breast cancer subtype.
Read more about the HER2 gene.
Breast cancer treatments are often given in a certain order, called stages. These stages are described using specific medical terms:
Your doctor may have you repeat HER2 testing at different points during breast cancer treatment. Results can help show whether the cancer is responding to treatment.
Read more about testing for HER2.
If you have early-stage breast cancer (cancer that has not spread throughout the body), the goal of your treatment will probably be to remove the tumor and prevent the cancer from coming back.
If your cancer has metastasized (spread to distant organs), you may also receive treatments to slow its growth. However, in cases of advanced breast cancer, the treatment goal may be different. You may have treatments that aim to make the tumor grow more slowly or ease your cancer symptoms.
The breast cancer treatment plan that is best for you will probably be very different from the treatment plan for someone else. Several factors go into deciding which cancer treatment plan is a good fit for your needs, including:
People with HER2-positive breast cancer often start treatment with targeted anti-HER2 therapy. These treatments are usually given as both neoadjuvant and adjuvant treatments. Targeted therapies can recognize and kill HER2-positive breast cancer cells.
The immune system naturally produces antibodies — proteins that help fight off harmful microorganisms like viruses and bacteria . Each antibody is made to recognize and attach to a specific substance, such as a particular protein or cell, and signal to the rest of the immune system to attack it.
Scientists can also make antibodies in a lab. These are called monoclonal antibodies, and they can be designed to attack cancer cells. Researchers have designed several anti-HER2 monoclonal antibodies that can recognize and attack the HER2 protein.
Trastuzumab (Herceptin) was the first monoclonal antibody approved by the U.S. Food and Drug Administration (FDA) to treat HER2-positive breast cancer. Since then, the FDA has approved additional anti-HER2 medications, including the antibody pertuzumab (Perjeta) and trastuzumab-dkst (Ogivri), a biosimilar of Herceptin.
These medications:
A treatment called Phesgo contains both trastuzumab and pertuzumab, along with hyaluronidase. Combining these treatments may increase the chances of removing all traces of cancer cells from your body. Because breast cancer cells can sometimes become resistant to one monoclonal antibody, using a combination can make the treatment more effective.
Monoclonal antibodies are often given as an intravenous (IV) infusion. The medication is injected directly into your veins. Each monoclonal antibody infusion usually takes between 30 and 90 minutes and is given at a hospital or clinic.
Scientists have developed newer forms of monoclonal antibodies that can be given subcutaneously (through an injection into the fatty tissue underneath the skin). This only takes a few minutes, and you may be able to have it done at your doctor’s office.
Phesgo is one such injection. Approved by the FDA in 2020, Phesgo offers a quicker alternative to IV infusions. In one study, 85 percent of people who received Phesgo said they preferred it over IV treatments, mainly because it took less time.
HER2 belongs to a family of proteins called kinases. Kinase inhibitors are targeted drugs that can stop kinase proteins from doing their jobs. Drugs in this category that may be used to treat HER2-positive breast cancer include neratinib (Nerlynx), tucatinib (Tukysa), and lapatinib (Tykerb).
Kinase inhibitors are often used to treat later-stage cancer or as a second-line treatment for earlier-stage tumors. These drugs usually come in pill form and are taken by mouth.
Antibody-drug conjugates (ADCs) combine targeted therapy and chemotherapy. ADCs contain a monoclonal antibody that helps the drug find cells that have the HER2 protein. The chemotherapy component of the drug then kills the cancer cell. ADC medications that may be given to people with HER2-positive breast cancer include T-DM1, also known as ado-trastuzumab emtansine (Kadcyla), and fam-trastuzumab deruxtecan-nxki (Enhertu).
Your doctor may prescribe an ADC as a second-line treatment for early-stage breast cancer or as a therapy for metastatic breast cancer. ADCs are usually delivered intravenously.
Several types of surgery may be used during breast cancer treatment. A lumpectomy removes the tumor along with a small part of the surrounding breast. In a mastectomy, the entire breast is removed. Either of these surgeries may later be followed by reconstructive surgery to restore the breast’s appearance.
Surgery may also involve removing the axillary lymph nodes — small structures in your armpit that help filter harmful substances. During your breast surgery, your doctor might perform a sentinel lymph node biopsy to check whether cancer cells have started to spread beyond the breast. If this biopsy is positive (meaning there are cancer cells in the sentinel node), the surgeon will remove all the axillary lymph nodes.
The goal of surgery is to remove as much of the tumor as possible from the breast. However, cancer cells can sometimes remain in the breast or other areas of the body. In these cases, adjuvant treatments may help get rid of any leftover cancer cells.
Radiation therapy uses beams of energy, such as X-rays, that can damage cancer cells. This treatment can help lower the risk of the tumor coming back. For people with HER2-positive breast cancer, the combination of targeted therapy, surgery, and radiation often works well to remove the cancer and keep it from coming back.
Individuals with HER2-positive breast cancer may benefit from chemotherapy treatments, known as chemo for short. Unlike targeted therapies that are designed to recognize specific types of cancer cells, chemotherapy is designed to kill any type of cancer cell.
If you have HER2-positive breast cancer, you may receive chemotherapy medication along with HER2 targeted therapy. For example, you may take the chemotherapy drug capecitabine (Xeloda) along with kinase inhibitors to treat advanced cancer or as a second-line therapy. Chemotherapy and HER2-targeted therapy drugs are sometimes given together in regimens such as:
HER2 is just one of several genetic changes a breast cancer cell may have. Breast tumors may also contain estrogen receptor (ER) or progesterone receptor (PR) proteins. ER and PR are types of hormone receptors. Cancer cells with either of these proteins use hormones (chemicals in the body that act as messengers) to grow. Hormone therapy (also known as endocrine therapy) can block these hormones, starving the cancer cells and making it difficult for them to grow.
If your breast cancer is both HER2-positive and hormone receptor-positive (either ER or PR), you may receive both targeted therapies and hormone therapies. Hormone therapy medications include tamoxifen or aromatase inhibitors such as anastrozole.
Hormone therapy may be given before or after surgery, alone, or with other treatments. This type of medication may be taken as maintenance therapy and may be continued for five years or more.
Researchers continue to study new treatments for HER2-positive breast cancer through oncology clinical trials. If you’d like to know about other treatment options, ask your oncologist about participating in a cancer research study. Clinical trials for breast cancer treatments may offer access to treatments that are not widely available. Treatment provided in clinical trials may be free or lower in cost.
Some people may worry they’ll receive a placebo (sugar pill) during a clinical trial. In most cases, people in clinical studies for cancer receive at least the current standard treatment for their cancer type. If there’s a chance you might receive a placebo, the researchers will let you know in advance.
Shared decision-making is a process where you and your doctor work together to decide on the best treatment plan for you. Your role in shared decision-making is to share your goals for treatment as well as your concerns and values. You can also ask questions about anything you don’t understand.
What is the best treatment for HER2-positive breast cancer? There’s no one-size-fits-all answer. The right approach depends on your individual situation, health, and preferences. Your doctor will help you learn more about your condition and treatment choices, answer questions, and help you weigh the potential risks and benefits of each option. Together, you will decide on the best cancer treatment plan for you. People who are involved in making decisions about their care are usually happier with their treatment experience.
Once you and your doctor have agreed on a breast cancer treatment plan, it is important to follow it closely. Keep taking the medication exactly as prescribed, for as long as your doctor recommends, even if you feel better. Stopping treatment too soon or not following instructions can lead to serious consequences:
If it’s hard for you to stick to your treatment plan, talk to your doctor before making any changes. They may be able to help you manage side effects or overcome other problems. Also, if you’re considering alternative treatments for HER2-positive breast cancer, always check with your oncologist first to make sure they’re safe and won’t interfere with your treatment.
Read more about prognosis and life expectancy with HER2-positive breast cancer.
MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.
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I was diagnosed with Her2 positive breast cancer 15 years ago. I did a double mastectomy and a year of Herceptin only treatments. I'm still here and so thankful for this drug. If you read how the… read more