Breast cancer isn’t a single disease. It’s actually a group of diseases.
When diagnosing breast cancer, one of the first steps doctors take is identifying the type of breast cancer. The type provides key information about how the cancer may behave.
About 13 percent of women in the United States will develop invasive breast cancer. Anyone can develop HER2-positive breast cancer, regardless of their sex.
Continue reading to learn more about HER2-positive breast cancer and what you can expect.
What is HER2-positive breast cancer?
When you have a breast biopsy, the tissue is tested for hormone receptors (HR). It’s also tested for something called human epidermal growth factor receptor 2 (HER2). Each can be involved in the development of breast cancer.
In some pathology reports, HER2 is referred to as HER2/neu or ERBB2 (Erb-B2 receptor tyrosine kinase 2). Hormone receptors are identified as estrogen (ER) and progesterone (PR).
The HER2 gene creates HER2 proteins, or receptors. These receptors help control the growth and repair of breast cells. An overexpression of HER2 protein causes out of control reproduction of breast cells.
HER2-positive breast cancers tend to be more aggressive than HER2-negative breast cancers. Along with tumor grade and cancer stage, HR and HER2 status help determine your treatment options.
Life expectancy and outlook
In the United States, it’s estimated that more than 42,000 women will die from breast cancer in 2020.
However, it’s important to know that aspects like life expectancy and your outlook can vary greatly based off many individual factors.
In the past, a diagnosis with HER2-positive breast cancer was associated with a poor outlook. Advances in drug therapies in recent years have improved the treatment options for HER2-positive breast cancer as well as the outlook for people with the disease.
According to the American Cancer Society, HER2-positive breast cancers are much more likely to respond to drugs that target the HER2 protein, despite the fact that they can grow and spread quickly.
This type of treatment is called targeted therapy. We’ll discuss it in more detail in a bit.
When considering your outlook, your doctor must analyze many other factors as well. Among them are:
- Stage at diagnosis. Your outlook is better when the breast cancer hasn’t spread outside the breast, or has spread only regionally at the start of treatment. Metastatic breast cancer, which is cancer that has spread to distant areas of the body, is harder to treat.
- Size and grade of primary tumor. This indicates how aggressive the cancer is.
- Lymph node involvement. Cancer can spread from the lymph nodes to distant organs and tissues.
- HR and HER2 status. Targeted therapies can be used for HR-positive and HER2-positive breast cancers.
- Overall health. Other health issues you may have may complicate treatment.
- Response to therapy. It’s hard to predict whether a particular therapy will be effective or produce intolerable side effects.
- Age. Younger women and those over 60 may have a worse outlook than middle-aged women, except for those with stage 3 breast cancer, according to one studyTrusted Source.
What treatments are available?
Your treatment plan will probably include a combination of therapies, such as:
- targeted treatments
Hormone treatments may be an option for cancer that’s also HR positive.
The size, location, and number of tumors help determine the need for breast-conserving surgery or mastectomy, and whether to remove the lymph nodes.
Radiation therapy can target any cancer cells that may remain after surgery. It can also be used to shrink tumors.
Chemotherapy is a systemic treatment. Powerful drugs can seek out and destroy cancer cells anywhere in the body. HER2-positive breast cancer generally responds well to chemotherapy.
Targeted treatments work to attack a specific type of cancer cell. In the case of HER2-positive breast cancer, these drugs would target cells expressing the HER2 protein.
The targeted treatments for HER2-positive breast cancer include:
Trastuzumab helps block cancer cells from receiving chemical signals that spur growth. It does this by attaching itself directly to the HER2 protein, thereby blocking incoming growth signals.
Trastuzumab was the first drug approved to specifically target the HER2 protein. It was a game-changer in the treatment of HER2-postive breast cancers.
Overall, using trastuzumab in combination with other treatment interventions, such as chemotherapy, is associatedTrusted Source with:
- longer survival
- lower 1-year death rate
- longer disease-free progression, which is when the cancer is still present but doesn’t get worse
- a high response rate to treatment
- a longer response to treatment
Pertuzumab is a drug that works much like trastuzumab. However, it attaches to a different part of the HER2 protein. It’s often used in combination with trastuzumab.
Ado-trastuzumab emtansine (Kadcyla)
This drug combines trastuzumab with a chemotherapy drug called emtansine. Trastuzumab delivers emtansine directly to the HER2-positive cancer cells.
It can be used to extend survival in those with metastatic breast cancer or breast cancer that’s returned. It can also be used in those with cancer that still remains (residual disease) after getting chemotherapy and HER2-targeted therapy, before surgery.
Fam-trastuzumab deruxtecan (Enhertu)
Fam-trastuzumab deruxtecan was approvedTrusted Source by the Food and Drug Administration (FDA) in late 2019. Like ado-trastuzumab, this drug combines trastuzumab with a drug called deruxtecan.
Fam-trastuzumab deruxtecan is used for HER2-postive breast cancer that has spread to other areas of the body, particularly after two or more HER2-targeted therapies have already been used.
It can also be given to people with HER2-positive breast cancer that surgery can’t remove.
Neratinib is a yearlong treatment that’s usedTrusted Source in the early stages of HER2-positive breast cancer. It’s given to adults who’ve already completed a treatment regimen that includes trastuzumab.
The aim of neratinib is to reduce the likelihood of a recurrence.
Targeted therapies usually work from outside the cell to block the chemical signals that promote tumor growth. Neratinib, on the other hand, affects chemical signals from within the cell.
Lapatinib blocks proteins that cause uncontrolled cell growth. It can help delay disease progression when metastatic breast cancer becomes resistant to trastuzumab.
It can be combined with oral chemotherapy or hormonal treatment to treat metastatic disease.
Tucatinib was just recently approvedTrusted Source by the FDA. Like neratinib and lapatinib, it also works inside the cell to block signals that lead to uncontrolled growth.
Tucatinib is used in combination with trastuzumab and capecitabine, a chemotherapy drug. It’s approved to treat HER2-positive breast cancer that is advanced, can’t be treated using surgery, or has metastasized.
Is it curable?
When discussing cancer treatment, it’s important to use caution when discussing whether a person’s cancer is “cured.” More often, you’ll see that the term “remission” is used.
A remission is when cancer symptoms are significantly reduced. It’s possible for remission to either be partial or complete. In a person with complete remission, all signs of cancer have disappeared.
A cancer is referred to as cured when there are no traces of cancer left in the body following treatment. If you’ve been in complete remission for 5 years or moreTrusted Source, your doctor may say that your cancer has been cured.
However, some cancer cells can remain present in the body following treatment. Because of this, it’s possible that the cancer can return at some point.
Due to this risk, your doctor may continue to monitor you for many years to make sure your cancer hasn’t returned.
Various factors, such as the stage of the cancer and treatment response, can influence whether a cancer goes into remission. It’s even possible for some people with metastatic HER2-positive breast cancer to experience complete remissionTrusted Source.
Remember that every person’s situation is different.
Can HER2-positive breast cancer recur?
HER2-positive breast cancer is more aggressive and more likely to recur, or return, than HER2-negative breast cancer. Recurrence can happen anytime, but it usually takes place within 5 years of treatment.
The good news is that recurrence is less likely today than ever before. This is largely due to the latest targeted treatments. In fact, most people treated for early stage HER2-positive breast cancer don’t experience recurrence.
If your breast cancer is also HR-positive, hormonal therapy may help reduce the risk of recurrence.
HR status and HER2 status can change. If breast cancer recurs, the new tumor must be tested so treatment can be reevaluated.
Survival rates of HER2-positive breast cancer
A cancer survival rate is a type of statistic that tells you what percentage of people with a diagnosis of a particular type of cancer are still alive after a certain period of time.
You’ll typically see cancer survival rates given over a 5-year period.
At this time, there’s been no specific research on survival rates for HER2-positive breast cancer alone. Current studies on breast cancer survival rates apply to all types.
According to the National Cancer Institute, these are the 5-year relative survival rates for women who received a breast cancer diagnosis between 2010 and 2016:
- Localized: 98.9 percent
- Regional: 85.7 percent
- Distant (or metastatic): 28.1 percent
- All stages combined: 90 percent
It’s important to remember that these are overall statistics. They can’t determine your personal outcome.
Also, long-term survival statistics are based on people who received a diagnosis years ago. Treatment is changing at a rapid pace and improving survival rates.
What is the outlook?
According to research estimates, more than 3.5 million women in the United States have a history of breast cancer.
The outlook for people with HER2-positive breast cancer varies. Advancements in targeted therapies continue to improve the outlook for people with early stage or metastatic disease.
Once treatment for nonmetastatic breast cancer ends, you’ll still need periodic testing for signs of recurrence. Most side effects of treatment will improve over time, but some may be permanent. You can work with your healthcare team to manage any lasting effects.
Metastatic breast cancer isn’t considered curable. Rather, treatment relieves and manages symptoms, and can continue as long as it’s working. If a particular treatment stops working, you can switch to another.
Barbara Jacoby is an award winning blogger that has contributed her writings to multiple online publications that have touched readers worldwide.