What Is the Treatment for HER2-Positive Breast Cancer?
Key takeaways:
About 15% of breast cancers are considered HER2-positive. This means the cancer cells have a high number of HER2 receptors on the cell surface.
HER2-positive breast cancer can be aggressive. But there are also highly effective treatments for this type of cancer that target the HER2 receptor.
These targeted treatments, in combination with more traditional cancer treatments, have significantly improved the survival rate for people with HER2-positive breast cancer.
The type of breast cancer you have plays a big role in your treatment options. Breast cancer can be categorized in a number of different ways — from the type of breast cell involved to the stage of the tumor. The receptor status is another important way to characterize your cancer. And this one can have a big effect on treatment.
Receptors are proteins found on the surface of cancer cells that bind with substances in the body to fuel tumor growth. There are three types of receptors that can be found on the breast cancer cell: estrogen, progesterone, and HER2. Even though having these receptors can seem like a bad thing, it actually is a helpful target for treatment.
What is HER2-positive breast cancer?
HER2 is a protein receptor that helps in cell growth. It’s naturally found on all breast cells. When a breast cell becomes cancerous, it might also have a higher amount of HER2 receptors than normal. These receptors help the cancer cells grow and spread.
When a certain breast cancer has an abundant amount of HER2 receptors on the cell surfaces, this is called HER2-positive breast cancer. About 15% of breast cancer cases in women are HER2-positive. If the cancer cells only have a small amount of the HER2 receptor, this is known as HER2-negative or HER2-low.
Both HER2-positive and HER2-low/negative breast cancers can also have other types of receptors that fuel cancer growth. This means they can be hormone receptor-positive for estrogen or progesterone receptors. When breast cancer has none of the three types of receptors, this is called triple-negative breast cancer.
What is the treatment for HER2-positive breast cancer?
The receptor status is important because many breast cancer treatments are directed at these receptors. This is called targeted therapy. And it can be particularly effective for HER2-positive breast cancer.
Targeted therapy gets its name because it targets specific genes or proteins on cancer cells. In HER2-positive breast cancer, targeted therapy is a class of medication that uses the HER2 protein to find and kill cancer cells.
Compared with chemotherapy, targeted therapy is more precise. Chemotherapy is designed to kill rapidly dividing cells. This means it kills cancer cells, but it also kills other noncancerous cells in the body. Targeted therapy is specific to the cancer cell, so it typically causes fewer side effects.
Targeted therapy isn’t the only treatment for HER2-positive breast cancer. For people who have stage 1-3 HER2-positive breast cancer, targeted therapy is often combined with other cancer treatments to create a more effective treatment plan:
Chemotherapy: Healthcare providers use chemotherapy alongside targeted therapy in all standard regimens for HER2-positive breast cancer. Many times, you receive chemotherapy before having the tumor removed through surgery. This helps select the most effective medications for someone’s particular cancer.
Hormone therapy: This type of treatment can be used if someone with HER2-positive cancer also has hormone-positive breast cancer. These medications target the estrogen and progesterone receptors on the surface of the cancer cell.
Surgery: Surgery can remove the tumor as well as nearby lymph nodes that might be affected. This is either done before or after initial treatment with targeted therapy and chemotherapy.
Radiation: This often follows surgery to kill any cancer cells left behind from surgery.
People who receive initial treatment with targeted therapy and chemotherapy will usually continue to receive some sort of targeted medication after their surgery. This helps ensure any cancer cells that may have spread outside the breast prior to surgery are also killed. This is done to prevent any more tumors from forming.
For people with metastatic HER2-positive breast cancer, targeted therapy and chemotherapy are the mainstay of treatment. Since metastatic cancer has spread to distant parts of the body, surgery and radiation are less effective. This is because they only treat one specific area of the body.
What is the survival rate for people with HER2-positive breast cancer?
HER2-positive breast cancer can be an aggressive, fast-spreading cancer. But for people with non-metastatic cancer, cure is possible. And the advances in targeted therapy for breast cancer has greatly improved cure rates.
The survival rate of HER2-positive breast cancer is affected by other characteristics of the breast cancer:
For people who are both HER2-positive and hormone receptor-positive, survival rate at 5 years is 91%.
For people who are HER2-positive and hormone receptor-negative, survival rate at 5 years is 86%.
“Nowadays, it’s considered a good thing to have HER2-positive breast cancer,” says Amy Tiersten, MD, hematologist and oncologist at Mount Sinai Hospital in New York City. “It really is a time to be very hopeful about being able to offer patients new drugs that vastly improve the outcome of treatment for HER2-positive breast cancer.”
The bottom line
Targeted therapy for HER2-positive breast cancer has changed the landscape of treatment for people with this type of cancer. They’re highly effective medications that have improved survival for both non-metastatic and metastatic disease. And since they target the cancer cell directly, they come with fewer side effects than other treatments. This can make a big difference in both time and quality of life for people living with breast cancer.
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References
National Cancer Institute. (n.d.). Cancer stat facts: Female breast cancer subtypes.
Patel, A., et al. (2020). The changing paradigm for the treatment of HER2-positive breast cancer. Cancers.
