Treatment for HER2-positive breast cancer depends on tumor size and spread but may involve a combination of chemotherapy, targeted therapy, monoclonal antibody therapy, and kinase inhibitors.

Specific genetic changes in cells can give doctors more information about breast cancer subtypes. One test examines the amount of HER2 gene present in breast cancer cells.

HER2 is short for human epidermal growth factor receptor 2. HER2 is a gene that makes the HER2 protein. HER2 protein is found on the surface of healthy cells and allows for normal cell growth and division.

Too much HER2 on the breast cancer cells causes a tumor.

Several treatments are available for HER2-positive breast cancer, which has good survival outcomes.

When researchers discovered that the HER2 gene had links to breast cancer growth, it led to the development of treatments that have significantly improved the survival rates for people with HER2-positive breast cancer.

This article examines HER2-positive breast cancer, treatments, and survival rates.

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Doctors can cure HER2-positive breast cancers using a multi-modality approach to care, typically involving surgery, systemic therapy, and radiation therapy.

Sometimes, surgeons can remove cancer, eradicating the disease. However, healthcare professionals recommend ongoing follow-up appointments to detect any recurrences.

It is possible to cure breast cancers when they remain confined to the breast and lymph nodes. Once breast cancer has spread to other bodily organs, doctors no longer consider it curable.

However, effective treatments are available for HER2-positive breast cancer.

Learn what happens at each stage of breast cancer.

The treatment plan will depend on the cancer stage. Staging considers the size of the tumor and whether it has spread. Staging helps guide decisions about treatment.

There have been significant advances in systemic therapies for HER2-positive breast cancers. This means that people with early-stage and metastatic HER2-positive breast cancers have treatment options.

HER2-positive breast cancer treatment may involve surgery, radiation therapy, chemotherapy, and targeted therapies.

Learn how tumor size relates to cancer stage.

Monoclonal antibodies

Monoclonal antibody treatments stop cancer from growing by attaching to the HER2 protein on cancer cells. Monoclonal antibody medications include:

  • Trastuzumab (Herceptin): This medication can help treat early or advanced-stage HER2 breast cancer. People may receive it in combination with chemotherapy.
  • Pertuzumab (Perjeta): Doctors administer this medication with trastuzumab (Herceptin) and chemotherapy.
  • Margetuximab (Margenza): Doctors use this medication to treat advanced-stage HER2-positive breast cancer. They may recommend it with chemotherapy when a person fails to respond to other targeted treatments.

Learn more about Herceptin and Perjeta.

Antibody drug conjugates

Antibody drug conjugates are a combination of chemotherapy and a monoclonal antibody. They attach to the HER2 protein and help the chemotherapy work more effectively. They include:

  • Ado-trastuzumab emtansine (Kadcyla): Oncologists use Kadcyla in the adjuvant setting after surgery if there is residual disease in the breast and if a person has had neoadjuvant treatment.
  • Fam-trastuzumab deruxtecan (Enhertu): People may receive this treatment if they have cancer that has spread to other parts of the body or cancer that doctors cannot remove surgically.

Learn more about metastatic breast cancer.

Kinase inhibitors

A kinase is a protein that prompts cells to take specific actions. HER2 is a type of kinase that tells a cell to grow. Kinase inhibitors work by blocking the action of HER2. Kinase inhibitors are oral medications such as:

  • Lapatinib (Tykerb): Doctors often use this medication in combination with trastuzumab and chemotherapy for advanced breast cancer.
  • Neratinib (Nerlynx): People may receive neratinib after they take trastuzumab for a year. Doctors may recommend it along with chemotherapy for cancer that has spread to other parts of the body.
  • Tucatinib (Tukysa): People may receive tucatinib with chemotherapy and trastuzumab. Doctors typically prescribe it for advanced breast cancer after completing another targeted treatment.

Learn more about anti-HER2 drugs and metastatic breast cancer.

Many variables can impact life expectancy after a cancer diagnosis, such as tumor size and whether the cancer has spread. An early diagnosis typically means a person has more treatment options and better outcomes.

Doctors use 5-year relative survival rates to estimate life expectancy. These survival rates compare how likely it is that someone with a type of cancer will still be alive 5 years after diagnosis compared to someone without cancer.

Whether the HER2-positive breast cancer is hormone receptor negative (HR-) or positive (HR+) will slightly affect life expectancy.

According to the National Cancer Institute, HER2-positive breast cancer that has not spread to any other organs in the body or the axillary lymph nodes has a 5-year relative survival rate of 98.8% if it is HR-positive and 97.3% if it is HR-negative.

If there is local spread to the axillary lymph nodes, the 5-year relative survival rate is 89.3% for HR-positive and 82.8% for HR-negative.

If cancer has spread to another part of the body, the 5-year survival rates are 46% and 38.8% for HR-positive and HR-negative, respectively.

Learn about HER2-negative breast cancer.

HER2 allows for normal cell growth and division. All healthy cells have HER2 proteins on their surface. The overexpression (growth) of the HER2 protein receptor on the breast cancer cells causes tumor growth.

The signs and symptoms of HER2-positive breast cancer are the same as any other type of breast cancer. If cancer cells have extra HER2 genes, healthcare professionals diagnose HER2-positive breast cancer.

HER2 tends to be a faster-growing type of breast cancer. High amounts of HER2 cause more rapid cell growth than other cancer cells.

HER2 status will guide a doctor’s decisions about treatment. Targeted treatments are available for HER2-positive breast cancer and may have fewer side effects than other therapies.

Learn more about ER-positive breast cancers.

It is impossible to predict who will develop HER2-positive breast cancer. Cancer starts when a genetic mistake in a cell causes it to grow abnormally. It is unclear why this happens in some people and not others.

However, some risk factors for breast cancer include:

  • genetic variant carriers
  • family history of breast cancer
  • longer exposure to estrogen, including early menstruation or late menopause
  • having dense breast tissue

Additionally, people under 40 have higher rates of HER2-positive breast cancer than other age groups.

Having a close family member with breast cancer increases the chance of developing breast cancer. However, HER2-positive breast cancer people do not genetically inherit this type of breast cancer.

Learn whether breast cancer genes skip a generation.

A person who has received a diagnosis of breast cancer will likely have many questions. Being informed about the treatment plan is important. People should feel comfortable asking as many questions as they need to.

Here are some questions a person with a diagnosis of HER2-positive breast cancer may want to ask a doctor:

  • Has biomarker testing been done? What are the results?
  • What is the stage of cancer? What does this mean?
  • What are the treatment options?
  • What are the pros and cons of each treatment approach?
  • How long will treatment last?
  • What is the plan to know whether a treatment is working or not?
  • How will the decision be made about whether a different treatment is needed?
  • Are there any clinical trials currently recruiting for this type of cancer?

Learn about racial diversity in breast cancer clinical trials.

HER2-positive breast cancer is a fast-growing breast cancer.

Effective targeted treatments exist for HER2-positive breast cancer. They work by blocking the action of HER2 genes to stop cancer growth.

Doctors consider HER2-positive breast cancers more aggressive, often requiring a multi-modality approach to care, including surgery, systemic therapy, and radiation therapy.

Survival rates for this type of breast cancer are good, particularly when a person receives a diagnosis and starts treatment early on.