HER2+ Early-Stage Breast Cancer

Side Effects

Like most cancer treatments, HER2+ breast cancer therapies may cause side effects. The good news is you can avoid some, minimize others and plan for inevitable challenges by working with your health care team before treatment begins. During treatment, report symptoms as soon as they occur so your doctor can help keep the condition from becoming serious — and make you as comfortable as possible.

Following are some common treatment-related side effects and suggestions for preventing or managing them.


Diarrhea can significantly affect your quality of life. When mild, diarrhea is an inconvenience. If left untreated, it can lead to serious problems, such as dehydration, loss of important nutrients, weight loss and fatigue.

Before starting treatment, make a plan of action with your health care team about the best time to begin and how best to prevent and control diarrhea. Let your treatment team know if you have an important event coming up. They may be able to adjust the timing of the treatment so you can enjoy your event without worrying about this side effect.

Once diarrhea occurs, consuming only clear liquids may help the lining of your intestines heal. Clear liquids include water, broth, popsicles, decaffeinated tea and gelatin. Over-the-counter medicines and fiber supplements are available to control diarrhea, but ask your doctor before taking anything. If your diarrhea is severe, your doctor may prescribe other medications or may check you for a Clostridium difficile (C. diff) infection.

You may be able to anticipate bouts of diarrhea based on prior episodes you have experienced during your treatments. Know where clean restrooms are located to avoid embarrassing situations.

Nausea and Vomiting

Nausea and vomiting may be caused by many drug therapies. These side effects occur as the result of a series of reactions between your stomach and your brain, which start when cancer drugs damage the cells lining the inside of the stomach.

It is much easier to prevent these side effects than to control them once they’ve started. Ask your doctor about antiemetics (anti-nausea drugs) to prevent and control them. To further protect yourself, you may consider nondrug approaches, such as progressive muscle relaxation, biofeedback, guided imagery, self-hypnosis and acupuncture. Eat several small meals rather than a few big meals a day, stay hydrated and avoid unpleasant odors. Try peppermints or ginger lozenges. Avoid eating your favorite foods after your chemotherapy is completed; they might not be your favorite foods anymore if you associate them with nausea and vomiting.

Hair Loss

Hair loss (alopecia) is most often caused by drug therapies and radiation therapy. It occurs because these treatments work by killing rapidly dividing cells, such as cancer cells. Because healthy cells in the hair follicles also divide rapidly, they may be damaged, too, which causes hair loss. Drug therapy typically causes loss of hair on the head, face and other parts of the body and may start seven to 10 days after the first cycle of treatment begins. Radiation therapy causes hair loss in the area of the body being treated. Hair loss is usually temporary.

To prepare yourself for hair loss, you may choose to cut your hair, shave your head or buy a wig. You may be more comfortable wearing a scarf, head wrap or hat. Ask your oncologist for a prescription for a wig. Using certain phrasing, such as “cranial (or skull) prosthesis due to alopecia caused by treatment for cancer” may make the wig eligible for insurance coverage. Contact the American Cancer Society or eBeauty.com about free wigs for patients undergoing cancer treatment.

Scalp cooling has been effective in preventing hair loss for some people receiving chemotherapy. Also called cold cap therapy, scalp cooling involves wearing a helmet-shaped cap filled with soft gel packs cooled to between -15 and -40 degrees Fahrenheit. The cap is worn before, during and after chemotherapy. The cold reduces blood flow to the head, which makes chemotherapy drugs less likely to reach and destroy the hair follicles.


Fatigue occurs primarily because the body needs extra energy to repair the healthy tissue damaged by cancer treatment. Different from the fatigue that healthy people feel, this type of fatigue usually lasts longer, is more severe and is unrelieved by sleep. If possible, perform regular exercise, such as walking or yoga, to help you feel more energized. Power walking for 30 minutes five times a week can diminish fatigue significantly. Nap for no more than 20 to 30 minutes at a time.


Neutropenia (low white blood cell count) commonly occurs in people treated with chemotherapy. Neutropenia is a low number of neutrophils, a type of white blood cell. Neutrophils play an important role in preventing infection throughout the body. Having an abnormally low number of them increases the risk of getting an infection, such as pneumonia, bronchitis, sinusitis or shingles. Neutropenia also makes it more difficult for an infection to resolve. The lower the neutrophil count, the greater the risk for infection. Wash your hands often. Wear gloves while cleaning or gardening. Avoid crowds and sick people. Avoid being too close to small children who can look healthy but are harboring germs.


Thrombocytopenia (causing bleeding/bruising/clotting issues) can occur from some chemotherapies because they may interfere with the body’s ability to make platelets, a type of blood cell. Thrombocytopenia can lead to bleeding and clotting problems, as well as easy bruising. Avoid taking Omega 3 supplements, aspirin and other blood thinners while you’re being treated, and inform your doctor about any other supplements you are taking.


Lymphedema (abnormal swelling) commonly occurs after surgery or radiation therapy. When lymph nodes are removed or damaged, lymph can build up, which can cause swelling in those areas. Your doctor may recommend wearing a compression garment that has been properly fitted by a certified lymphedema therapist. It may be helpful to elevate the swollen limb. Talk with your doctor about low-level laser therapy to help relieve swelling in the arms, which often occurs after mastectomy.


Neuropathy is pain or discomfort caused by damage to the peripheral nervous system, which includes the nerves that control movement and feeling in the arms and legs. Symptoms include numbness, pain, burning, tingling and loss of feeling in the hands or feet. Additionally, if you are diabetic, this side effect can worsen existing symptoms. Contact your oncologist about prescription medicines designed to relieve neuropathic pain.

Sexuality Issues

Sexuality issues may develop during breast cancer treatment, especially if you associate your breasts with your self image. After treatment, your breasts may not look the same. They may be scarred or may have been removed. As a result, how you feel about your body and how you relate intimately to your partner may change. Reduced sexual desire and feeling less desirable are common, but that doesn’t mean you have to accept them as normal. Vaginal dryness may also be an issue that may be alleviated by using daily vaginal moisturizers as well as vaginal lubricants during sexual intercourse. Your doctor may not bring up sexuality issues, so it is important that you do. Sometimes the goal isn’t intercourse and climaxing; intimacy is very important. Cuddling together is underrated.

Cognitive Dysfunction

Cognitive dysfunction (chemo brain) is the feeling of not being able to think clearly or having trouble remembering details. Although chemo brain is often connected with chemotherapy, it can occur as a result of many types of cancer treatment and can vary in degree of severity. Use a daily planner to keep track of things, and make lists to help you stay organized. Solve crossword puzzles or number games to strengthen your mental ability. Focus on one thing at a time instead of multitasking. Keep in mind, too, that stress can cause similar symptoms.

Mouth Sores

Mouth sores (oral mucositis) are small cuts or ulcers that can affect the gums, tongue, roof of the mouth or lips. Mouth sores sometimes begin as mild pain or burning followed by white patches that may become large red lesions. Pain may range from mild to severe, making it difficult to talk, eat or swallow. Avoid spicy and rough-textured foods. Brush your teeth with a soft-bristled toothbrush. Your doctor may suggest a mouth rinse or a medication that is topical or coats the lining of your mouth.


Anemia (low red blood cell count) is common with chemotherapy. Red blood cells carry oxygen to the body’s tissues. Anemia can cause many symptoms, most often fatigue and weakness, and can be temporary or long lasting.

Skin Reactions

Skin reactions may occur from many types of treatment and may include redness and irritation (similar to sunburn), rash and itchy or dry, flaky skin. Moisturize your skin often, and avoid lotions and laundry detergents containing perfumes or dyes.

Joint Pain

Joint pain (arthralgia) may range from mild to severe and typically resolves when treatment ends. You may be on treatment for many years, however, so it’s important to discuss pain management with your doctor. Keep a journal, noting when and where the pain occurs, the severity, how long it lasts and what might have triggered it.


Nurture Your Emotional Well-Being

Breast cancer may challenge you as much emotionally as it does physically. You may feel both negative and positive emotions during treatment, including hope, peace, appreciation and clarity about life and goals. You may realize you have strength you never dreamed you had, or develop lasting relationships with people you’ve met as a result of your diagnosis. However, keep in mind that how you react to your diagnosis and treatment will be unique. Everyone is different. Allow yourself to nurture your well-being and express your feelings freely because being emotionally healthy will help you better cope with cancer-related issues, including managing side effects.

Anger can occur before, during and sometimes long after your cancer treatment. Give yourself permission to own and express your anger — without feeling guilty. Find safe ways to release it. Punch or hit a pillow with a foam bat, yell in private or engage in intense physical activity. Share your feelings with a friend.

Anxiety is often described as feeling nervous, stressed, worried and/or tense. Symptoms may include faster heartbeat, upset stomach, difficulty concentrating, tightness in your chest area, shakiness or dizziness. Being anxious may make it difficult to cope with treatment or daily life and may prevent your body from healing properly after treatment. Explore relaxation techniques, such as yoga or massage. Consider seeing a mental health specialist.

Depression is more complex than just feeling sad. It’s most likely to occur when you’re not getting relief from treatment side effects, and it can also be a side effect of some treatments. It’s crucial to talk with your health care team about excessive crying or feeling hopeless, especially if such feelings last more than a couple of days. Get immediate medical attention if you have thoughts of death or suicide.

Emotional overload is a feeling of being out of control. Learning new medical terms, going to multiple medical appointments and undergoing treatment may be overwhelming. Ask your doctor to explain your diagnosis and treatment plan to help you feel more comfortable with what is ahead.

Fear is a common reaction to finding out you have cancer and going through treatment. You may fear pain during or after treatment, not being able to do daily activities, a change in appearance (hair loss or scars), fertility issues or sexuality challenges. Share your feelings with a mental health specialist or a support group.

Grief is the feeling of distress or sorrow due to the loss of something. It is normal to grieve the loss of your health, your appearance or your ideas of what your future would be without cancer. Ask your friends and family for support.

Guilt is the sense that you’ve done something wrong. You may feel you are upsetting loved ones or that you are a burden to them. You may feel guilty about not having a positive attitude all the time. Be kind to yourself. Talk with other survivors or a therapist.

Loneliness is a feeling of being alone and isolated. You may feel your diagnosis prevents you from living the life you once had. If friends avoid visiting or calling, you might feel no one understands. Talking to others who have the same type of cancer as you may help.


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