What is HER2-Positive Breast Cancer and How is it Treated?
Written by: Dr. Syeda Jannat Shayyan
Breast cancer is one of the most common cancers affecting women globally. It develops when abnormal cells in the breast grow uncontrollably, forming a tumor. However, not all breast cancers are the same. Among the various types, HER2-positive breast cancer stands out due to its specific characteristics and treatment approaches. In this article, we’ll explore what HER2-positive breast cancer is, its implications, and the treatment options available.
Understanding Breast Cancer
Breast cancer begins when cells in the breast tissue grow abnormally, forming a mass called a tumor. It can spread to nearby tissues or even other parts of the body through the lymphatic system or bloodstream if left untreated. The keyword ‘breast cancer’ generally encompasses different types, each categorized based on the molecular features of the cancer cells, including the presence of hormone receptors or other proteins that affect how the cancer grows.
One crucial marker in determining the type of breast cancer is the human epidermal growth factor receptor 2, commonly known as HER2. This protein promotes the growth of cancer cells. In normal circumstances, HER2 helps regulate healthy breast cell growth. However, when a breast cancer is HER2-positive, it means that there is an overexpression of the HER2 protein, leading to aggressive and rapid growth of the tumor.
What is HER2-Positive Breast Cancer?
HER2-positive breast cancer is a subtype of breast cancer that tests positive for the HER2 protein, a gene mutation that makes the cancer cells grow more rapidly. About 20% of all breast cancer cases are HER2-positive. This type of cancer tends to grow and spread more quickly than HER2-negative breast cancers, making early diagnosis and targeted treatment crucial.
HER2-positive breast cancer is typically more aggressive than hormone receptor-positive types. However, advancements in targeted therapy have dramatically improved the prognosis for patients diagnosed with this subtype, reducing the risk of recurrence and increasing survival rates.
Causes and Risk Factors for HER2-Positive Breast Cancer
While the exact cause of HER2-positive breast cancer is still unknown, research suggests that genetic mutations in the HER2 gene can lead to the overproduction of the HER2 protein, which in turn causes uncontrolled cell growth. Several risk factors increase the likelihood of developing HER2-positive breast cancer, including:
- Genetics: A family history of breast cancer, particularly with cases of HER2-positive cancers, increases the risk.
- Age: The risk of breast cancer, including HER2-positive cancer, increases with age.
- Lifestyle Factors: Smoking, alcohol consumption, and obesity have been linked to a higher risk of breast cancer.
- Radiation Exposure: Previous exposure to radiation therapy, especially in the chest area, increases breast cancer risk.
Symptoms of HER2-Positive Breast Cancer
HER2-positive breast cancer shares many symptoms with other types of breast cancer, and early detection is key to successful treatment. Common signs and symptoms include:
- A lump or thickening in the breast or underarm area.
- Changes in the size, shape, or appearance of the breast.
- Nipple discharge, other than breast milk, particularly if it’s clear or bloody.
- Pain in the breast or nipple.
- Skin dimpling or redness over the breast.
- Unexplained swelling or thickening in one part of the breast.
If you experience any of these symptoms, it’s essential to consult a healthcare professional for further evaluation, as early detection leads to better outcomes.
Diagnosis of HER2-Positive Breast Cancer
Diagnosing HER2-positive breast cancer involves several tests to determine the nature and extent of the cancer. Some of the most common diagnostic tests include:
- Biopsy: A small sample of tissue is taken from the breast tumor to analyze the presence of cancer cells.
- Immunohistochemistry (IHC) Test: This test determines how much HER2 protein is present in the cancer cells. The results are scored from 0 to 3+, with scores of 2+ or 3+ indicating a HER2-positive status.
- Fluorescence In Situ Hybridization (FISH) Test: This test measures the number of copies of the HER2 gene in cancer cells, confirming the HER2 status.
- Imaging Tests: Mammograms, ultrasounds, and MRIs are typically used to visualize the tumor and assess the spread of the disease.
Treatment Options for HER2-Positive Breast Cancer
The treatment plan for HER2-positive breast cancer typically involves a combination of therapies. Thanks to advancements in targeted therapies, treatment outcomes for HER2-positive patients have significantly improved over the years. Here’s a look at the most common treatment options:
1. Targeted Therapy
Targeted therapy is one of the most effective treatments for HER2-positive breast cancer. These drugs specifically target the HER2 protein and block its ability to stimulate tumor growth.
- Trastuzumab (Herceptin): This drug was one of the first targeted therapies developed for HER2-positive breast cancer. It binds to the HER2 protein, preventing it from stimulating cancer cell growth. Studies have shown that trastuzumab improves overall survival rates and reduces the risk of recurrence.
- Pertuzumab (Perjeta): Often used in combination with trastuzumab and chemotherapy, pertuzumab enhances the effectiveness of HER2-targeting therapy by preventing the HER2 protein from pairing with other proteins to promote cancer growth.
- Ado-trastuzumab emtansine (Kadcyla): This drug combines trastuzumab with a chemotherapy drug to deliver targeted treatment directly to cancer cells, minimizing damage to healthy cells.
- Lapatinib (Tykerb): This drug is used for advanced HER2-positive breast cancer, especially when other therapies have not been effective. It blocks the HER2 protein’s signals, slowing the growth of cancer cells.
2. Chemotherapy
Chemotherapy involves the use of drugs to destroy rapidly growing cancer cells. It is often combined with targeted therapy for HER2-positive breast cancer. Chemotherapy may be given before surgery (neoadjuvant therapy) to shrink the tumor or after surgery (adjuvant therapy) to eliminate any remaining cancer cells.
3. Surgery
Surgical options for HER2-positive breast cancer include lumpectomy (removing the tumor while preserving the breast) or mastectomy (removal of one or both breasts). The choice of surgery depends on the size and location of the tumor, as well as patient preferences and overall health.
4. Radiation Therapy
Radiation therapy uses high-energy beams to target and kill cancer cells. It is typically recommended after surgery to eliminate any remaining cancer cells in the breast, chest wall, or lymph nodes.
5. Hormone Therapy
Although hormone therapy is not effective for all HER2-positive breast cancers, it may be used in cases where the cancer is also hormone receptor-positive. Drugs like tamoxifen or aromatase inhibitors can block hormones that promote cancer growth.
Prognosis and Survival Rates
The prognosis for HER2-positive breast cancer has improved significantly due to advances in targeted therapies. Historically, HER2-positive breast cancer was considered more aggressive with a poorer prognosis than HER2-negative types. However, with the advent of drugs like trastuzumab, survival rates have increased dramatically.
The five-year survival rate for HER2-positive breast cancer is approximately 80%, depending on the stage of diagnosis and response to treatment. Early detection and a personalized treatment approach are key factors in improving outcomes.
Living with HER2-Positive Breast Cancer
Living with HER2-positive breast cancer can be challenging, but with the right support system and treatment plan, many patients live long, fulfilling lives after diagnosis. It’s crucial to:
- Follow your treatment plan: Adhering to your doctor’s recommended treatment plan is essential for managing the disease.
- Stay informed: Keeping up with the latest research and treatment options can help you make informed decisions about your care.
- Seek support: Connecting with support groups, counselors, or therapists can provide emotional and mental support during your journey.
Conclusion
HER2-positive breast cancer is an aggressive form of breast cancer, but thanks to modern advancements in targeted therapies, the prognosis has improved significantly. Early diagnosis, targeted treatments, and a combination of therapies tailored to the patient’s needs offer hope for long-term survival and improved quality of life.
If you or a loved one has been diagnosed with HER2-positive breast cancer, it’s essential to consult with healthcare professionals to explore all available treatment options and take proactive steps towards managing the disease. Always prioritize early detection and follow up with regular screenings, especially if you’re at higher risk.
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