Essential Facts You Need to Know About HER2-Positive Breast Cancer

June 17, 2023

Thanks to research, HER2-positive breast cancer can now be treated effectively. However, every person’sperson’s cancer is different and may return.

If breast cancer recurs or progresses, it’s important to get a new biopsy and test for HER2 again. This information helps doctors decide on the best treatment options.

What is HER2?

Cancer researchers use HER2 status to help determine your prognosis. It’sIt’s not the only factor, but it’s important because HER2-positive cancer tends to grow and spread faster than other types of breast cancer.

Your doctor will order HER2 testing as part of your breast cancer diagnosis after you find a lump or routine mammogram spots. Your doctor will need to take a sample of the tumor tissue for testing, which requires a biopsy.

Two types of HER2 testing are available: immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). IHC tests attach a chemical dye to the HER2 protein so that a pathologist can read the results under a microscope. FISH uses a fluorescent marker to locate HER2 amplification in the cancer cells. A pathologist can then compare the test results with reference ranges to determine if your tumor is HER2-positive or negative.

In addition, some HER2 tests have a high error rate. False positive assays can deprive a patient of a treatment that could extend her life. In contrast, false-negative assays can result in patients receiving a treatment that may not be effective.

HER2 results are only as accurate as the biopsy tissue samples from which they’re-they’re based. You should discuss your test results with your oncologist and, if necessary, get the HER2 tested again.

How is HER2 diagnosed?

Most people with breast cancer are diagnosed when they notice a lump in their breast or when their doctor spots a tumor during a routine mammogram. When cancer is diagnosed, it’s assigned a stage based on how large the tumor is and how far it has spread. Besides the staging system, doctors look at a cancer’scancer’s HER2 status to determine available treatment options.

When cancer has extra copies of the HER2 gene, it overproduces HER2-related proteins that can cause cancer cells to grow uncontrollably. These HER2-positive cancers are more aggressive and harder to treat than those that don’tdon’t have excess HER2-related proteins.

HER2 status can be determined through several laboratory tests, including an immunohistochemistry (IHC) test and a fluorescence in situ hybridization (FISH) test. The IHC test measures how much HER2 is on the cancer cell’s surface and gives it a score. If the IHC score is zero or one, cancer is considered HER2-negative. If the score is two or higher, the cancer is HER2-positive.

There are a variety of treatments for HER2- breast cancer. Some standard chemotherapy drugs can be effective for HER2-positive breast cancer, and targeted therapies such as trastuzumab and pertuzumab. HER2 status can change over time, so doctors will retest a patient’spatient’s tumor if it recurs or spreads to ensure that treatment is still working.

What are the treatment options for HER2-positive breast cancer?

The foundational studies that led to the understanding of HER2 helped scientists recognize the importance of targeting this protein in cancer treatment. Many treatment options are available once considered an aggressive breast cancer with poor patient outcomes.

HER2 testing is done routinely as part of a biopsy to determine the type of invasive breast cancer a person has. It is not done for noninvasive ductal carcinoma in situ (DCIS). HER2 results are important because they provide key information about the molecular subtype of a person’sperson’s breast cancer, influencing how it may behave.

When HER2 is overexpressed in cancer cells, they grow more quickly and are more likely to spread to other body parts. These characteristics make HER2-positive cancers harder to treat than different types of breast cancer.

A person with stage 1 or 2 HER2-positive breast cancer will most likely be treated with chemotherapy before surgery and HER2-targeted therapy afterward. HER2-targeted therapies — trastuzumab with or without pertuzumab, lapatinib, or capecitabine — work by attaching themselves to HER2 and blocking the growth signals cancer cells need to survive.

In some cases, HER2-positive breast cancers can resist standard chemotherapy drugs, which is why a combination approach may be needed. Despite this, it is still possible for people with HER2-positive breast cancer to experience complete remission. It is important to discuss treatment plans with your doctor and be sure to follow up regularly for any new or recurring symptoms.

What are the side effects of HER2-positive breast cancer treatment?

A cancer’scancer’s type tells a doctor how fast it grows and spreads. Knowing your cancer’scancer’s HER2 status is important because it affects the kind of treatment you get. HER2-positive cancers are more aggressive than others, but recent drug therapy advances have improved the outlook for people diagnosed with this type of cancer.

HER2 is found in the cells that line the breast ducts, and it helps regulate the growth of these cells. But a mutation or extra copies of the HER2 gene cause breast cancer cells to overproduce this protein, which leads to faster growth and more aggressive tumors. About 13 percent of invasive breast cancers are HER2-positive and are more likely to affect younger women. In addition, HER2-positive tumors are more likely to be hormone-sensitive than other types of breast cancer.

Your doctor will diagnose HER2-positive breast cancer through a physical exam and blood tests. Your doctor may recommend a biopsy if the results show you have cancer. A biopsy is when your doctor removes a small amount of breast tissue to test for cancer cells. The biopsy can be done with a fine needle in a procedure called fine-needle aspiration or with a core needle biopsy.

HER2-positive breast cancer tends to grow and spread more quickly than other types of breast cancer, but the five-year survival rate is high, especially for people diagnosed early. This is largely due to effective targeted treatments.

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