HER2-Positive Breast Cancer - Early Signs, Risk Factors, Diagnosis, and Treatment Explained

Overview: What Is HER2-Positive Breast Cancer?

Breast cancer is one of the most common cancers affecting women worldwide. Among its different types, HER2-positive breast cancer is a form that grows and spreads more aggressively. The good news is that today, with advanced targeted treatments and early detection, survival rates and recovery have improved greatly.

HER2 stands for human epidermal growth factor receptor 2. It is a protein found on the surface of breast cells that helps them grow and repair. In HER2-positive breast cancer, the body makes too much of this protein, causing cancer cells to grow and divide quickly.

HER2-positive breast cancer accounts for about 15–20% of all breast cancers. While it is considered more aggressive, it also responds very well to targeted therapies developed in recent years. This makes early detection crucial.

What Are the Types of HER2-Positive Breast Cancer?

HER2-positive breast cancers are classified based on whether they also depend on hormones (estrogen and progesterone) for growth:

• HER2-positive, hormone receptor-positive (HR+): These cancers have too much HER2 and also respond to estrogen or progesterone. Treatment usually combines targeted therapy, hormone therapy, and other treatments.
• HER2-positive, hormone receptor-negative (HR–): These cancers only depend on HER2 and tend to grow faster. Targeted therapies play the main role in treatment.

What Are the Causes of HER2-Positive Breast Cancer?

The exact cause of HER2-positive breast cancer is not fully understood. Cancer develops when normal breast cells undergo genetic changes that make them grow uncontrollably.

In this case, a change in the HER2 gene leads to the production of extra HER2 proteins on the cell surface. This triggers rapid cell growth and division, leading to cancer. HER2-positive breast cancer is typically not inherited and is not directly linked to lifestyle, though lifestyle and reproductive factors can influence overall breast cancer risk.

What Are the Risk Factors for HER2-Positive Breast Cancer?

Several factors can raise the risk of developing HER2-positive breast cancer:

• Age: Most common in women over 40, though it can affect younger women too.
• Genetics: Family history of breast cancer or inherited mutations (such as BRCA1 and BRCA2) can raise overall breast cancer risk.
• Family history: Having a mother, sister, or daughter with breast cancer increases risk.
• Hormone replacement therapy (HRT): Long-term use of combined estrogen-progestin hormone replacement therapy may raise risk.
• Reproductive history: Early menstruation, late menopause, or having no children.
• Lifestyle factors: Obesity, alcohol use, lack of exercise, and poor diet.
• Radiation exposure: Especially to the chest area.

What Are the Symptoms of HER2-Positive Breast Cancer?

In its early stages, HER2-positive breast cancer may not cause any symptoms. As it grows, common signs may include:

• A lump or thickening in the breast
• Changes in breast shape or size
• Redness or swelling of the breast
• Nipple changes (inversion, discharge, or pain)
• Skin dimpling (like an orange peel)

Advanced symptoms, if the cancer spreads, may include bone pain, cough, shortness of breath, or unexplained weight loss. Any new breast change should be checked by a doctor right away. Early diagnosis leads to better outcomes.

How Is HER2-Positive Breast Cancer Diagnosed?

Doctors use several steps to confirm a diagnosis of HER2-positive breast cancer:

• Clinical breast exam: A doctor checks for lumps or changes in the breast/skin/nipples.
• Mammogram: X-ray images of the breast can detect suspicious growths.
• Breast Ultrasound: Helps distinguish between solid masses and fluid-filled cysts.
• Breast MRI: Provides detailed imaging, often used for high-risk patients.
• Biopsy: A small sample of tissue is taken and tested in the lab to confirm cancer. A biopsy also helps doctors determine the cancer’s grade and whether it has receptors for HER2 protein, which guide treatment decisions.
• HER2 testing: Special lab tests (immunohistochemistry and FISH) are done on biopsy samples to check if the cancer is HER2-positive. Newer techniques, such as next-generation sequencing (NGS), may also be used in some centers to confirm HER2 status.

Additional scans such as CT, PET, or bone scans may be used to see if the cancer has spread.

Staging of HER2-Positive Breast Cancer

Staging describes how far the cancer has spread, from Stage 0 (non-invasive) to Stage IV (spread to distant organs).

• Stage 0: Non-invasive (ductal carcinoma in situ).
• Stage I: Small tumor, confined to the breast.
• Stage II: Larger tumor, may involve nearby lymph nodes.
• Stage III: Locally advanced, involving skin, chest wall, or multiple lymph nodes.
• Stage IV: Cancer has spread (metastasized) to other parts of the body.

Grading refers to how abnormal the cancer cells look under a microscope. High-grade tumors tend to grow faster. Staging and grading help doctors decide the best treatment plan.

What Are the Treatment Options for HER2-Positive Breast Cancer?

Treatment usually involves a combination of therapies tailored to each patient’s stage, age, and overall health.

Surgery

• Lumpectomy (breast-conserving surgery): Removal of only the tumor and some surrounding tissue, preserving most of the breast.
• Mastectomy: Removal of the entire breast. Types of mastectomies include simple mastectomy, modified radical mastectomy, skin- and nipple-sparing mastectomy, endoscopy-assisted mastectomy, and prophylactic mastectomy.
• Oncoplastic surgery: Combines breast cancer surgery with cosmetic techniques to maintain breast shape.
• Sentinel lymph node biopsy: Checks whether cancer has spread to the lymph nodes near the breast.

Medical Treatments

• Chemotherapy: Uses drugs to kill fast-growing cancer cells. Often given before (neoadjuvant) or after surgery (adjuvant).
• Targeted therapy: The most important treatment for HER2-positive cancers. Drugs such as trastuzumab, pertuzumab, trastuzumab-emtansine (T-DM1), trastuzumab-deruxtecan (T-DXd), and lapatinib or neratinib directly target HER2 proteins, slowing or stopping cancer growth.
• Immunotherapy: Immunotherapy is not routinely used in HER2-positive breast cancer, except in clinical trials or in certain HER2-low, triple-negative subtypes.
• Hormone therapy: Used if the cancer is also hormone receptor-positive.

Radiation Therapy

High-energy rays are used to kill cancer cells, usually after surgery to prevent recurrence.

Proton Therapy: When Is It Applicable?

Available at Apollo Proton Cancer Centre, proton therapy uses protons instead of X-rays to deliver radiation more precisely to cancer cells. This allows doctors to target the tumor while minimizing damage to healthy surrounding tissue, including the heart and lungs.

Proton therapy may be considered for HER2-positive breast cancer in the following situations:

• When the tumor is located close to critical organs such as the heart or lungs, especially in left-sided breast cancers.
• In younger patients, to reduce long-term side effects from radiation exposure.
• For patients who have already received radiation to the chest and require additional treatment.
• In complex cases where precision is essential to reduce radiation-related complications.

While proton therapy is not required for all patients with HER2-positive breast cancer, it can be especially beneficial in selected cases where traditional radiation may pose higher risks.

What is the Prognosis for HER2-Positive Breast Cancer?

Thanks to targeted treatments, the outlook for HER2-positive breast cancer has improved dramatically.

• Early-stage HER2-positive breast cancer: With modern therapy, the 5-year survival rate can be 90% or higher.
• Advanced-stage HER2-positive breast cancer: In advanced stages, prognosis has significantly improved with newer therapies, though cure may not always be possible.

Prognosis depends on stage at diagnosis, age, overall health, and response to treatment. Regular follow-up care is essential.

Screening and Prevention of HER2-Positive Breast Cancer

Early detection saves lives. Screening helps find breast cancer before symptoms appear.

• Mammograms: Women aged 40 and older should get regular mammograms, which can spot early signs of cancer, even before it can be felt.
• Breast Self-exams: Regular breast self-examinations are encouraged as they can help detect changes in the breast.
• Lifestyle changes: Maintain a healthy optimal weight, exercise regularly, avoid alcohol and smoking.
• Genetic testing: High-risk women, including those with a strong family history of cancer, may consider BRCA testing.

For International Patients

People from around the world come to Apollo Hospitals for the treatment of HER2-positive breast cancer. Our international patient services team will guide you all the way from seeking the first virtual connect all the way to treatment in India and then returning home post treatment.

Services include:

• Medical opinions and scheduling: Pre-arrival medical review of reports and imaging.
• Travel and logistics: Assistance with visa invitation letters, airport transfers, and nearby accommodation options.
• Dedicated international patient coordinators to guide through each step.
• Language and cultural support: Interpreter services in multiple languages. Clear, simple explanations at every stage with written care plans.
• Financial coordination: Transparent treatment estimates and packages when possible. Support with international payment methods and insurance coordination.
• Continuity of care: Shared records, imaging, and treatment summaries for home doctors. Telemedicine follow-ups for convenience after returning home.

Frequently Asked Questions (FAQs)

1. What is the survival rate for HER2-positive breast cancer?

With targeted therapy, survival rates are very high in early stages, often above 90% at 5 years. Even advanced cases are now more treatable than before.

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

Side effects vary. Chemotherapy may cause hair loss, nausea, or fatigue. Targeted therapy can sometimes affect the heart, so regular monitoring is done. Radiation may cause skin irritation or tiredness.

3. Can HER2-positive breast cancer come back?

Yes, recurrence is possible, but the risk is much lower with modern treatments. Regular follow-up visits and scans are important.

4. How long does recovery take after treatment?

Recovery depends on the type of treatment. After surgery, most women return to daily activities within a few weeks. Fatigue from chemotherapy or radiation may last longer, but improves with time.

5. Is HER2-positive breast cancer curable?

In early stages, yes, many women are cured with the right treatment. In advanced stages, while it may not be fully curable, treatment can control the disease for years and improve quality of life.

6. Should I consider genetic testing if I have HER2-positive breast cancer?

Genetic testing (such as for BRCA mutations) may be recommended if you have a strong family history. It helps guide treatment and assess risk for relatives.