HER2-Positive Breast Cancer: What Now?

I remember a patient, Sarah, sitting in my office, her hands clasped tightly in her lap. The words “breast cancer” were already a shock, but then we added “HER2-positive,” and a fresh wave of questions, and understandably, fear, washed over her face. “Doctor,” she’d said, her voice a little shaky, “what on earth does that mean?” It’s a question I hear often. If you’re here, reading this, you might be asking the same thing, either for yourself or someone you love. Let’s walk through it together.

Hearing you have HER2-positive breast cancer can feel like a lot. And it is. But knowledge is power, so let’s break it down.

Table of Contents

So, What Exactly Is HER2-Positive Breast Cancer?

Alright, let’s get into what HER2-positive breast cancer actually means. Imagine every cell in your breast has tiny antennas on its surface. One type of these is called the human epidermal growth factor receptor 2, or HER2 for short. Normally, these HER2 proteins help healthy breast cells grow, divide, and repair themselves. It’s all part of the body’s usual upkeep.

Now, in HER2-positive breast cancer, something’s gone a bit haywire with the gene that makes these HER2 proteins – the HER2 gene. It starts making too many copies of itself. More genes mean more HER2 proteins on the cells. Think of it like those antennas suddenly becoming super-powered, picking up way too many growth signals. This makes the breast cells grow and divide too quickly, and that’s how a cancerous tumor can form.

This type of breast cancer tends to be a bit more aggressive, meaning it can grow faster and, if we don’t catch it, it has a higher chance of spreading (what we call metastasis) beyond the breast to other parts of your body. It’s a specific subtype of invasive breast cancer.

How Common Is It?

You’re definitely not alone if this is your diagnosis. Each year, many women are diagnosed with invasive breast cancer. Of those cases, a fair chunk – somewhere around 15% to 20% – will be HER2-positive. It’s much less common in men, but it can happen. The good news? We’ve learned a lot about how to treat it, especially if we find it early.

What Might You Notice? Signs and Symptoms

Sometimes, HER2-positive breast cancer, like other breast cancers, can be sneaky and not cause obvious symptoms, especially at first. That’s why regular check-ups and mammograms are so important. But when it does make itself known, here’s what you or your doctor might pick up on:

A new lump or mass in your breast. It might feel as small as a pea, or a bit larger.
A general change in the size, shape, or feel of your breast.
A lump or a sort of thickening in or near your breast, or even in your armpit area, that doesn’t go away after your period.
Skin changes on your breast or nipple:
It might look dimpled or puckered, a bit like orange peel.
It could be scaly, red, or inflamed. Sometimes the skin color might look darker.
A hardened area under the skin that feels a bit like a marble.
Any unusual discharge from your nipple, especially if it’s bloody or clear.

If you notice any of these, please don’t wait. Come and see us. It might be nothing serious, but it’s always best to check.

What Causes It and Am I at Risk?

The direct cause of HER2-positive breast cancer is that mutation in the HER2 gene we talked about, leading to too many HER2 proteins. Why that gene decides to change… well, that’s the million-dollar question researchers are still working hard to answer fully.

As for risk factors, they’re generally the same as for other types of breast cancer. It’s important to remember, you can have several risk factors and never develop breast cancer, or have none and still get it. Life’s not always fair that way. Some things that might increase risk include:

Genetics: Having an inherited gene mutation like BRCA1 or BRCA2.
Personal history: If you’ve had breast cancer before.
Certain breast conditions: Things like atypical ductal hyperplasia.
Menstrual history: Starting periods very early or menopause very late.
Hormone replacement therapy: Using it for a prolonged time.
Alcohol: Regularly having more than one alcoholic drink a day.
Radiation history: Previous radiation therapy to the chest, maybe for something like lymphoma.

A Word About Complications

Because HER2-positive breast cancer can be more aggressive, there’s a concern it might spread, or metastasize. In fact, sometimes, that’s how it’s discovered – after it’s already moved to places like the brain, lungs, liver, or bones. Metastatic breast cancer, especially to the brain, can be very serious, which is why early detection and treatment are key.

How We Figure This Out: Diagnosis and Tests

If we suspect breast cancer, the first step is usually a breast biopsy. This means taking a small sample of the breast tissue. A pathologist – a doctor who’s an expert at looking at cells under a microscope – will then examine these cells.

If they find cancer cells, the next crucial step for HER2-positive breast cancer is to check for those HER2 proteins. We have specific lab tests for this:

Immunohistochemistry (IHC) test: This test uses special stains to light up the HER2 proteins on the cancer cells. The pathologist then scores how much HER2 protein is there.
A score of 0 or 1+ means low levels, and it’s considered HER2-negative.
A score of 2+ is borderline or equivocal. It means there are moderate levels, and we’d usually do another test to be sure.
A score of 3+ means high levels of HER2 protein, and this is classified as HER2-positive.
Fluorescence In Situ Hybridization (FISH) test: This test is often used to confirm a 2+ IHC result, or sometimes as the first test. It looks directly at the HER2 genes in the cancer cells to see if there are too many copies. If there are extra copies, it’s HER2-positive.

These tests are so important because knowing your HER2 status helps us choose the most effective treatments.

Tackling HER2-Positive Breast Cancer: Treatments

Once we know it’s HER2-positive breast cancer, we can get very specific with treatment. Because this type has that HER2 protein as a target, we have some really smart drugs. Treatment plans vary based on things like the cancer stage and your overall health, but often include:

Targeted Therapy: These are the game-changers for HER2-positive cancer.

Monoclonal antibodies: Drugs like trastuzumab (Herceptin) and pertuzumab (Perjeta) are designed to attach to the HER2 proteins on the cancer cells. This can stop the cells from growing and also alert your immune system to attack them.
Antibody-drug conjugates (ADCs): These are like guided missiles. They combine a HER2-targeting antibody with a chemotherapy drug. The antibody delivers the chemo directly to the cancer cells, which can mean fewer side effects on healthy cells. Ado-trastuzumab emtansine (Kadcyla) or fam-trastuzumab deruxtecan-nxki (Enhertu) are examples.
Tyrosine kinase inhibitors: These are smaller molecules that can get inside the cancer cells and block the growth signals from within. Lapatinib (Tykerb) or neratinib (Nerlynx) are in this group.

Chemotherapy: Often used alongside targeted therapy, especially if the cancer is larger or has spread. We might use it before surgery (neoadjuvant chemotherapy) to shrink the tumor, or after surgery (adjuvant chemotherapy) to catch any stray cancer cells.
Surgery: To remove the tumor (lumpectomy) or the entire breast (mastectomy).
Radiation Therapy: May be used after surgery to kill any remaining cancer cells in the breast area.
Hormone Therapy: If your cancer is also hormone receptor-positive (ER+ or PR+), then hormone therapy will likely be part of your plan too.

What About Side Effects?

Every treatment can have side effects, and they vary from person to person and drug to drug. Some common ones with HER2-targeted therapies can include fatigue, diarrhea, or heart issues (which we monitor very closely). Chemotherapy has its own set of potential side effects like nausea or hair loss.

We’ll talk through all the possibilities for your specific treatment. And please know, we have ways to manage many of these side effects. That’s where palliative care comes in – it’s specialized medical care focused on providing relief from the symptoms and stress of a serious illness. It’s not just for end-of-life care; it’s about improving quality of life throughout treatment.

We’ll discuss all options for you, and tailor a plan that’s best suited to your situation.

What’s the Outlook?

This is often one of the first questions, and it’s a perfectly natural one. When we talk about “cure” in cancer, we often mean putting the cancer into remission (where there are no signs of it) for many years.

The outlook for HER2-positive breast cancer has improved so much thanks to targeted therapies. If it’s caught before it spreads (localized), the five-year survival rate is very high – over 90% according to the U.S. National Cancer Institute data. That means more than 90 out of 100 people are alive five years after diagnosis.

If it has spread to nearby lymph nodes (regional), the rates are still good. If it has spread to distant parts of the body (distant or metastatic), it’s more challenging, but treatments are constantly improving, offering more time and better quality of life. Survival rates can also differ a bit if the cancer is also hormone receptor-positive (HR+) or negative (HR-). About half of HER2-positive breast cancers are also HR+.

It’s important to remember that this cancer can sometimes come back (recur), even years later. So, ongoing follow-up is really important.

Can We Prevent HER2-Positive Breast Cancer?

Honestly, probably not directly. Because HER2-positive breast cancer is caused by that specific gene mutation, there’s not a particular lifestyle change we know of that can stop that gene from changing. Researchers are always looking, though!

However, you can take steps to lower your overall risk of breast cancer in general:

Breast awareness: Know your breasts. Do regular self-exams, and don’t skip your mammograms. Early detection is always your best friend.
Healthy weight: Maintaining a weight that’s healthy for you is a big plus.
Good nutrition: A diet rich in veggies, fruits, lean protein, and calcium-rich dairy can help. Try to limit red and processed meats.
Get moving: Regular physical activity has been shown to lower breast cancer risk.
Limit alcohol: If you drink, try to keep it moderate – generally, no more than one drink a day for women.

Living With This Diagnosis

A diagnosis of HER2-positive breast cancer is a journey, no doubt about it. You’ll have good days and tough days. You might feel tired from treatment, or overwhelmed by it all. That’s okay. Here are a few things that might help:

Rest up: Cancer and its treatments can be exhausting. Listen to your body and rest when you need to.
Eat well, even when it’s hard: Good nutrition helps your body stay strong. If your appetite is off, talk to us or a dietitian.
Manage stress: Find what works for you – maybe gentle walks, meditation, or a hobby.
Lean on your support system: Friends, family, support groups… you don’t have to do this alone. Ask us about cancer survivorship programs; they can be a fantastic resource.

When to Call Your Doctor

You’ll have regular appointments, of course. But call us anytime you notice new changes in your breasts or any new, persistent symptoms in your body. For example, breast cancer that spreads to the lungs might cause a new cough, shortness of breath, or chest pain.

When to Head to the ER

If you have a severe reaction to treatment – like non-stop vomiting leading to dehydration, or a very high fever – it’s best to go to the emergency room.

Take-Home Message: Key Things to Remember About HER2-Positive Breast Cancer

Okay, that was a lot of information. If you’re feeling a bit dazed, that’s completely normal. Here are the main things I’d like you to take away:

HER2-positive breast cancer means cancer cells have too much of a protein called HER2, which makes them grow fast.
It’s a more aggressive type, but we have specific, effective targeted therapies for it.
Diagnosis involves a biopsy and special lab tests (IHC and/or FISH) on the cancer tissue.
Treatment often combines targeted therapy, chemotherapy, surgery, and/or radiation.
The outlook has significantly improved, especially with early detection.
You can’t directly prevent the HER2 mutation, but general breast health practices are always wise.
Don’t hesitate to ask us questions. Any question. We’re here to help you understand.

Questions to Ask Your Healthcare Team

When you meet with your doctors, it’s good to have some questions ready. It helps you feel more in control. You might consider asking:

Can you confirm my exact HER2 status? (e.g., IHC 3+, or FISH positive)
What is my hormone receptor status (ER/PR)?
How do these details affect my specific prognosis and treatment plan?
What treatment(s) are you recommending for me, and why?
What are the potential side effects, and how will we manage them?
Should I think about participating in any clinical trials for HER2-positive breast cancer?
What support services are available to me and my family?

You’re not alone in this. We have a whole team ready to support you, and science is making incredible strides every year. We’ll face this together.