Watching for early symptoms of breast cancer — including human epidermal growth factor receptor 2 (HER2)-positive breast cancer — involves more than feeling for lumps in your breast. Your body may give you different warning signs you should be aware of. It’s important to be familiar with how your body normally looks and feels for you, so you can tell when something changes.

While you may be able to detect some symptoms of breast cancer, you can’t always tell whether and what type of breast cancer you have from the symptoms alone. Testing during diagnosis is the only way to learn what type of breast cancer you have.

Continue reading to learn more about early symptoms of HER2-positive breast cancer.

What Is HER2-Positive Breast Cancer?

HER2-positive breast cancer is a subtype of breast cancer. People with this type of cancer have cancer cells that make a protein called human epidermal growth factor receptor 2. It also goes by other names, such as ERBB2. The HER2 protein helps to control how cancer cells grow and divide.

HER2-positive breast cancers are aggressive, fast-growing types of cancer. This type of breast cancer may grow faster, metastasize (spread to other parts of the body), and recur (come back) more often than others. Because of this, it’s important to find HER2-positive breast cancer early.

Most symptoms of breast cancer can also be caused by conditions that aren’t cancer. However, it’s important to check with your health care provider as soon as you notice any new changes or symptoms.

What follows are six symptoms of early-stage HER2-positive breast cancer to watch for.

1. Breast Lump

A new lump in your breast is the most common symptom of breast cancer. A hard but painless lump with irregular edges is most likely to be a malignant (cancerous) tumor. However, some breast cancer lumps might feel soft and round.

If you feel a lump in your breast, it’s important to talk to your health care provider right away. They may suggest a mammogram (an X-ray test of the breast) and additional testing.

Even though breast cancer isn’t the most common cause of a breast lump, your provider can help you find out the cause. Fast-growing cancers, like HER2-positive breast cancer, can result in a lump that grows quickly.

2. Breast Swelling

Swelling in part or all of your breast can be a symptom of breast cancer. If you have breast swelling, your breast may appear larger than usual. Swelling can occur in breast cancer even if you don’t feel a lump.

Breast swelling can be a symptom of inflammatory breast cancer — a rare type of invasive ductal carcinoma. People with inflammatory breast cancer may be more likely to have HER2-positive breast cancer cells. However, you won’t know if you have HER2-positive breast cancer until after diagnosis and testing.

3. Pain in Your Breasts or Nipples

Breast cancer usually doesn’t cause pain in your breasts or nipples. Breast lumps caused by breast cancer are usually not painful. However, it’s possible that you may experience a painful lump.

Even though breast or nipple pain is more commonly caused by the menstrual cycle and benign (noncancerous) conditions, it’s important to tell your health care provider about any pain you experience.

4. Skin Changes on Your Breasts

Changes in the texture of the skin on your breasts can be a sign of some types of breast cancer. Skin dimpling can look like pits or sunken areas in your skin. This sign is also called “peau d’orange” — French for “orange peel” — because the skin may look like the skin of an orange. Your skin may also have a thicker texture.

Skin dimpling is most often a sign of a breast infection called mastitis. However, it can also be a sign of inflammatory breast cancer.

Breast cancer can cause other changes to the skin on your breasts and nipples, such as discoloration, irritation, flaking, or dryness.

Talk to your health care provider as soon as possible if you notice any changes to the skin on your breasts and nipples.

5. Nipple Changes

Sometimes breast cancer can cause changes in your nipple. The most common nipple change people see as a symptom of breast cancer is nipple retraction — when your nipple turns inward. About 20 percent of people have nipples that naturally turn inward. However, it could be a symptom of cancer if it happens suddenly or only affects one breast.

Nipple discharge may also be a symptom of breast cancer. If you’re not breastfeeding, it’s not normal to have any fluid coming out of your nipples. While changes to your nipple and nipple discharge don’t always indicate breast cancer, it's important to talk to your health care provider as soon as possible if you notice any changes.

6. Swollen Lymph Nodes

You may have swelling around your armpit or collarbone if breast cancer spreads to the nearby lymph nodes. These are small, bean-shaped organs found throughout the body that are part of the immune system. You may notice swelling before you’re able to feel a lump in your breast.

When breast cancer metastasizes (spreads), it usually first goes to the lymph nodes in the armpit or collarbone. Since HER2-positive breast cancer tends to grow and spread quickly, you may experience lymph node swelling as an early symptom of breast cancer.

How Is Breast Cancer Diagnosed?

If you notice any of the previously mentioned symptoms of breast cancer, your health care provider will order follow-up tests to discover the cause of your symptoms. If these tests don’t rule out breast cancer, a breast biopsy can diagnose breast cancer. During a breast biopsy, your provider will take a small sample of breast tissue to examine under a microscope.

How Do You Learn Your HER2 Status?

Several different tests can check for the HER2 protein in your cancer cells (also known as your HER2 status). Your health care provider can order these tests on a biopsy sample or from the tumor after they remove it with surgery.

There are two main tests used to determine whether your cancer is HER2-positive or HER2-negative — fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) tests.

If your breast cancer cells are HER2-positive, it means that your cancer is more likely to grow quickly and recur (come back) after treatment. About 15 percent to 20 percent of breast cancers are HER2-positive.

What Is the Best Treatment for HER2-Positive Breast Cancer?

There are several treatment options for HER2-positive breast cancer. Some of these treatments are also used for other types of breast cancer, such as surgery, chemotherapy, radiation therapy, and hormone therapy.

Targeted therapy is a type of breast cancer treatment that works by targeting specific proteins that help cancer cells grow and divide, such as the HER2 protein. If you have HER2-positive breast cancer, you may be eligible for targeted therapy.

Examples of targeted therapies for HER2-positive breast cancer include:

• Ado-trastuzumab emtansine (Kadcyla)
• Fam-trastuzumab deruxtecan (Enhertu)
• Lapatinib (Tykerb)
• Margetuximab-cmkb (Margenza)
• Neratinib (Nerlynx)
• Pertuzumab (Perjeta)
• Trastuzumab (Herceptin)
• Trastuzumab, pertuzumab, and hyaluronidase-zzxf (Phesgo)
• Tucatinib (Tukysa)

Read more about specific medications in this list of treatments for breast cancer.

The best treatment for you may involve a combination of different treatments, including techniques to help manage side effects. Talk to your cancer care team about the right treatment plan for you.

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 70,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Which early symptoms of breast cancer did you notice? Did any symptoms prompt you to see your health care provider before your scheduled breast cancer screening? Start a conversation by posting on your Activities page.