If you’ve recently been diagnosed with early-stage HER2-positive breast cancer, you may be wondering what “HER2-positive” really means and how that influences treatment.
HER2 is one of several important characteristics doctors look at when diagnosing breast cancer. Knowing whether your cancer is HER2-positive helps your care team understand how the cancer may behave and, importantly, whether you may benefit from treatments that specifically target HER2.
What is HER2?
When breast cancer is diagnosed, a pathologist looks at several receptors on the cancer cells. The three major receptors doctors consider are estrogen receptor (ER), progesterone receptor (PR), and HER2.
Dr. Pooja Advani, a breast medical oncologist, describes receptors as being like “proteins or docking stations.” Just as a boat docks at a designated station, certain substances in the body can bind to these receptors.
For example, hormones such as estrogen can bind to the estrogen receptor and send signals that encourage cancer cells to grow and divide.
HER2 is another type of receptor. When breast cancer is HER2-positive, the cancer cells have higher-than-normal levels of HER2. HER2-positive breast cancer represents approximately 15% to 20% of breast cancers.
Why does HER2 status matter?
HER2 is important because it is more than a characteristic of the cancer. It’s also a treatment target.
“We now have targeted therapies that we can give to women who are HER2 receptor positive,” Dr. Advani explains.
These HER2-targeted treatments are designed to specifically interfere with the HER2 pathway that helps cancer cells grow. They have become an important part of treatment for many people with HER2-positive breast cancer.
Your HER2 status is considered alongside your hormone receptor status and other features of your cancer. For example, a breast cancer can be both HER2-positive and hormone receptor-positive, or HER2-positive and hormone receptor-negative.
These differences matter because they can influence which treatments are recommended.
What happens if you have HER2-positive early breast cancer?
With early breast cancer, treatment is generally intended to remove the cancer and reduce the risk of it coming back.
Your treatment plan may include a combination of:
- HER2-targeted therapy
- Chemotherapy
- Surgery
- Radiation therapy
- Hormone therapy if your cancer is hormone receptor-positive
Not everyone will need every treatment. Your care team considers factors such as the size of your tumor, whether cancer has spread to nearby lymph nodes, your hormone receptor status, and other features of the cancer.
Why might treatment come before surgery?
One question many people have is why their doctor might recommend chemotherapy and HER2-targeted therapy before removing the tumor.
For some people with HER2-positive early breast cancer, treatment before surgery, called neoadjuvant therapy, is an important part of the treatment plan.
Dr. Advani explains that doctors particularly consider this approach when the tumor is larger than 2 centimeters and/or cancer is found in the lymph nodes.
“For the most part, we try to prioritize them getting treatment, such as chemotherapy with or without immunotherapy, for HER2-positive directed therapy prior to surgery,” she says.
There are several potential benefits to treating the cancer before surgery. Treatment may shrink the tumor, address cancer cells that may have traveled elsewhere in the body and give doctors an opportunity to see how the cancer responds to therapy.
That response can also provide important information for determining what treatment may be needed after surgery.
What if surgery comes first?
Not everyone with HER2-positive breast cancer needs treatment before surgery.
The order of treatment can depend on your individual diagnosis and how advanced the cancer appears to be at the time it is found.
“When we’re not certain what the patient is going to get,” Dr. Advani explains, “most practices will start with the surgeon who can clarify the clinical stage.”
From there, your care team can determine whether you should see a medical oncologist before surgery to discuss neoadjuvant treatment or proceed with surgery first.
If surgery is performed first, you will typically meet with a medical oncologist afterward to discuss additional treatment. A radiation oncologist may also be involved, depending on your situation.
What questions should you ask your care team?
A HER2-positive diagnosis can come with a lot of new information. It can help to ask your doctors to explain exactly what your pathology and staging results mean for you.
Consider asking:
- Is my cancer HER2-positive and hormone receptor-positive or negative?
- How large is my tumor?
- Are my lymph nodes involved?
- What is my clinical stage?
- Should I receive treatment before surgery?
- Which HER2-targeted therapy is recommended for me?
- Will I need chemotherapy?
- Will I need radiation or hormone therapy?
- How will we know whether my treatment is working?
- What treatment will I need after surgery?
Your HER2 status is just one piece of the picture. Your tumor size, lymph-node status, hormone receptor status, and other characteristics all help your care team determine the treatment approach that is right for you.
Disclaimer: The information provided in this article is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Outcomes4Me is not acting as your caregiver, and any suggestions or guidance offered should not replace the advice of your healthcare provider or qualified medical professional. Always seek the guidance of your physician or other qualified health provider with any questions you may have regarding a medical condition.
