HER2-Positive Breast Cancer : Symptoms, Causes, Treatment

What are the symptoms of HER2-positive breast cancer?

HER2-positive breast cancer is a specific subtype of breast cancer that is characterized by overexpression of the human epidermal growth factor receptor 2 (HER2) protein. Symptoms of HER2-positive breast cancer generally include:

1. Breast Changes: These can include a lump or thickening in the breast or underarm area.
2. Skin Changes: Such as redness, dimpling, or puckering of the skin on the breast.
3. Nipple Changes: Such as inversion of the nipple (turning inward), discharge other than breast milk, or changes in the skin around the nipple.
4. Pain: While not always present, some women may experience breast or nipple pain.
5. Enlarged lymph nodes: Swelling or lumps in the lymph nodes under the arm or around the collarbone, indicating possible spread of cancer.

It’s important to note that symptoms can vary among individuals, and early detection through regular breast exams and mammograms is crucial for timely diagnosis and treatment. If you notice any changes in your breasts, it’s advisable to consult a healthcare provider promptly.

What are the causes of HER2-positive breast cancer?

The causes of HER2-positive breast cancer are not fully understood, but several factors may contribute to its development:

1. Genetic Factors: Genetic mutations or alterations can lead to overexpression of the HER2 gene, resulting in increased production of the HER2 protein. This overexpression is characteristic of HER2-positive breast cancer.
2. Hormonal Factors: While HER2-positive breast cancer is not hormone-receptor positive (like estrogen or progesterone receptor-positive cancers), hormonal influences and signaling pathways can play a role in the development and progression of breast cancer, including HER2-positive subtypes.
3. Environmental and Lifestyle Factors: Factors such as exposure to radiation, certain chemicals, or environmental pollutants may contribute to the development of breast cancer, including HER2-positive types. Lifestyle factors like alcohol consumption, obesity, and lack of physical activity may also play a role.
4. Family History and Genetics: A family history of breast cancer or certain genetic mutations (such as BRCA1 and BRCA2 mutations) can increase the risk of developing HER2-positive breast cancer.
5. Age and Gender: Breast cancer, including HER2-positive types, tends to be more common in women and increases with age.
6. Other Risk Factors: Other factors such as reproductive history (early menarche or late menopause), never having children or having them late in life, and certain benign breast conditions can also influence breast cancer risk.

Understanding these potential causes can help in prevention strategies, early detection, and personalized treatment approaches for HER2-positive breast cancer. Regular screening and maintaining a healthy lifestyle are important steps in reducing overall breast cancer risk.

How is the diagnosis of HER2-positive breast cancer made?

The diagnosis of HER2-positive breast cancer is typically made through a combination of clinical evaluation, imaging tests, and laboratory tests. Here are the steps involved in making a diagnosis:

1. Clinical Evaluation: A patient’s medical history, physical examination, and review of symptoms are performed by a healthcare provider to determine the presence of breast cancer.
2. Mammography: A mammogram is an X-ray of the breast tissue that helps to detect abnormalities in the breast tissue.
3. Breast Ultrasound: An ultrasound uses high-frequency sound waves to produce images of the breast tissue. It is often used to further evaluate abnormalities detected on a mammogram or to assess the size and location of a breast tumor.
4. Biopsy: A biopsy is a procedure in which a small sample of tissue is removed from the breast tumor for further examination. There are different types of biopsies, including:
   • Fine-needle aspiration biopsy (FNAB): A thin needle is inserted into the tumor to collect a sample of cells.
   • Core needle biopsy (CNB): A thicker needle is used to collect a larger sample of tissue.
   • Surgical biopsy: A surgical incision is made in the breast to remove a sample of tissue.
5. Immunohistochemistry (IHC): The biopsy sample is then examined under a microscope using immunohistochemical stains to detect the presence of HER2 protein on the surface of cancer cells. This test is usually performed on a section of tissue from the biopsy sample.
6. HER2 Testing: The IHC test measures the amount of HER2 protein present on the surface of cancer cells. If the test shows that 3+ (or 100%) of the cancer cells have high levels of HER2 protein, it indicates that the cancer is HER2-positive.
7. Fluorescence In Situ Hybridization (FISH): If the IHC test is equivocal or uncertain, FISH may be performed to confirm the results. FISH tests for specific genetic changes in the HER2 gene.
8. Confirmation of Diagnosis: After all test results are obtained, a pathologist reviews them and confirms whether the cancer is HER2-positive or HER2-negative.

It’s essential to note that HER2 testing should be done on both primary and metastatic tumors, as HER2 status can change between these two stages.

In summary, a comprehensive approach involving clinical evaluation, imaging tests, biopsy, immunohistochemistry, and molecular testing helps diagnose HER2-positive breast cancer accurately.

What is the treatment for HER2-positive breast cancer?

The treatment for HER2-positive breast cancer typically involves a combination of surgery, chemotherapy, and targeted therapy. The specific treatment plan will depend on various factors, including the stage of the disease, the size and location of the tumor, and the patient’s overall health.

Surgery:

1. Lumpectomy: Removing the tumor and a small amount of surrounding tissue (breast-conserving surgery).
2. Mastectomy: Removing the entire breast.

Chemotherapy:

1. Adjuvant chemotherapy: Given after surgery to reduce the risk of recurrence.
2. Neoadjuvant chemotherapy: Given before surgery to shrink the tumor and make it easier to remove.

Targeted Therapy:

1. Trastuzumab (Herceptin): A monoclonal antibody that targets HER2 protein, used in combination with chemotherapy.
2. Pertuzumab (Perjeta): A monoclonal antibody that targets HER2 protein, used in combination with trastuzumab and chemotherapy.
3. Ado-trastuzumab emtansine (Kadcyla): A targeted therapy that combines trastuzumab with the chemotherapy drug DM1.
4. Lapatinib (Tykerb): A tyrosine kinase inhibitor that targets HER2 protein.

Hormone Therapy:

1. Tamoxifen: A hormone therapy that can be used in combination with chemotherapy or targeted therapy.
2. Aromatase inhibitors: Medications that block the production of estrogen in postmenopausal women.

Radiation Therapy:

1. Whole-breast radiation: Radiation therapy after lumpectomy to reduce the risk of recurrence.
2. Regional radiation: Radiation therapy to treat lymph nodes or other areas where cancer has spread.

Immunotherapy:

1. Neratinib (Nerlynx): An oral medication that targets HER2 protein and can be used in combination with other treatments.

The treatment plan for HER2-positive breast cancer typically involves a multidisciplinary approach, with a team of healthcare professionals working together to develop a personalized treatment plan.

It’s essential to note that HER2-positive breast cancer is often more aggressive than other types of breast cancer, so a comprehensive treatment plan is crucial to achieve optimal outcomes.