HER – Who is “she”?
HER-2, known as human epidermal growth factor receptor 2, is a proto-oncogene that is found in small amounts on the surface of normal cell membranes in every human body and plays a key role in the cell growth factor signaling pathway.
What is HER2-positive breast cancer?
When the HER-2 gene is highly expressed in cancer cells, excessive HER-2 protein is produced on the cell membrane, stimulating wild growth of cancer cells and increasing their aggressiveness. Therefore, HER-2 positive breast cancer patients are more aggressive, more likely to have recurrence and metastasis, and have a shorter survival period, which clinicians call poor prognosis.
About 20-30% of breast cancer patients have HER-2-positive tumors.
All treatment decisions should be made after HER-2 status is known
Detection of HER-2-positive breast cancer
Although HER-2-positive breast cancer is very aggressive, targeted anti-HER-2 therapy can bring the prognosis of HER-2-positive patients closer to that of HER-2-negative patients and improve their chances of survival, so all breast cancer patients should be tested for HER-2 status as soon as possible.
How to perform HER-2 testing
There are two methods to detect HER-2: immunohistochemistry (IHC) and in situ hybridization (ISH)
Immunohistochemistry (IHC): detects the amount of HER-2 protein.
In situ hybridization (ISH): detects HER-2 gene and determines the amplification of HER-2 gene. The more commonly used in situ hybridization (ISH) is fluorescence in situ hybridization (FISH).
Both of these methods are available for the first test.
If the immunohistochemistry (IHC) test result is “3+” or the in situ hybridization (ISH) test is positive, then the test is HER-2 positive.
If the IHC result is “2+”, further in situ hybridization (ISH) testing should be performed.
If the ISH result is positive, the test is positive for HER-2.
If the immunohistochemistry (IHC) result is “0/1+”, then the test is HER-2 negative.
Treatment for HER-2-positive breast cancer
Although breast cancer is a malignant tumor, there is nothing to fear. With the development of modern medicine and technology, the cure rate of early stage breast cancer is about 90%. As long as you actively cooperate with your doctor and persist in treatment, it is entirely possible to beat the cancer and recover your health.
Treatment methods for breast cancer include surgery, radiation therapy, chemotherapy, endocrine therapy and molecular targeted therapy
Surgery: Surgery to remove cancerous tissues is the main treatment for breast cancer, which is a local treatment and the only treatment that can cure breast cancer.
Radiation therapy: Radiation therapy for short is to destroy tumor cells with high energy rays to achieve the purpose of killing them. Radiotherapy is a local treatment and is generally used after surgery. Post-operative radiotherapy can reduce the recurrence of breast cancer. It can also be used for advanced stage of breast cancer that cannot be operated.
Chemotherapy: chemotherapy for short is a kind of treatment that uses chemical drugs to kill tumor cells and inhibit their growth and reproduction, which belongs to systemic treatment. However, the limitation of chemotherapy is that it can kill normal cells while killing tumor cells, resulting in toxic side effects such as hair loss, nausea, vomiting, diarrhea and anemia.
Endocrine therapy: Endocrine therapy belongs to the systemic treatment measures of breast cancer. Some breast cancer tumor cells need estrogen and progesterone stimulation to grow. By surgically removing the ovaries or adjusting the estrogen and progesterone levels in the body with certain drugs, it is possible to slow down or even stop the growth of tumor cells, and endocrine therapy is applicable to hormone receptor (ER/PR) positive breast cancer.
Molecularly targeted therapy: A treatment modality that uses specific genes or gene expressions in tumor cells as therapeutic targets. Because molecularly targeted therapy targets tumor cells and avoids normal cells, it is more effective and has fewer toxic side effects.
The current standard of care for HER-2 positive breast cancer is a trastuzumab-based regimen, and for early-stage patients, the standard treatment regimen is one year.
Trastuzumab is the first targeted drug approved for the treatment of HER-2-positive breast cancer worldwide. It targets the HER-2 protein on tumor cells and inhibits tumor cell proliferation by blocking the HER-2 transmission pathway.
Trastuzumab can make the prognosis of HER-2-positive breast cancer patients close to that of HER-2 negative patients. One year of trastuzumab treatment has been shown to significantly increase the chance of cure, reduce the risk of recurrence by half and the risk of death by one-third in patients with early-stage HER-2-positive breast cancer; prolong the survival and improve the quality of life of patients with advanced HER-2-positive breast cancer.