Herceptin Therapy for Breast Cancer

For adjuvant and metastatic breast cancer

In This Article

A bottle of the Herceptin drug.
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Herceptin, also known by its generic name trastuzumab, is a chemotherapy infusion medication approved to treat adjuvant breast cancer and metastatic breast cancer. It is essentially a protein that targets and binds to the HER2 protein (human epidermal growth factor receptor2). About 1 in 4 people with breast cancer have HER2-positive breast cancer or protein human epidermal growth factor receptor2. HER2 is an aggressive form of breast cancer that grows and spreads rapidly.


Herceptin treats early-stage breast cancer that is HER2-positive regardless of whether it's spread to the lymph nodes. A long-term follow-up study published in 2017 showed that one year of treatment with this drug significantly improved disease-free survival.

For adjuvant breast cancer, Herceptin is used as part of a treatment course during chemotherapy.

Herceptin also is approved to treat metastatic breast cancer in two ways—in combination with the chemotherapy medication paclitaxel or alone for people who have already received chemotherapy for metastatic breast cancer.


Herceptin is part of a class of drugs that are called biologic therapies. This drug works by hunting down only those cancer cells that have HER2/neu receptors on their outer surface. The HER2 gene makes a protein receptor on the surface of a tumor cell. This receptor signals the cell to divide and multiply.

When there is too much HER2 in breast cancer tissue, cell division goes out of control and happens much too quickly. Herceptin attaches to the HER2 receptors and blocks the growth signal, preventing more cell division and slowing the progression of cancer.


Herceptin is a pale white or yellow fluid that's given through a chemotherapy infusion. Your first dose will be given slowly in a 90-minute session to see how well you tolerate the drug and to watch for allergic reactions.

If you do well with it, your following infusions can be given in 30-minute sessions.

Side Effects 

Some patients receiving Herceptin for breast cancer had the following side effects: 

  • Fever
  • Feeling sick to your stomach (nausea)
  • Throwing up (vomiting)
  • Infusion reactions
  • Diarrhea
  • Infections
  • Increased cough
  • Headache
  • Feeling tired
  • Shortness of breath
  • Rash
  • Low white and red blood cell counts
  • Muscle pain

Some patients receiving Herceptin for metastatic stomach cancer had the following side effects:

  • Low white blood cell counts
  • Diarrhea
  • Feeling tired
  • Low red blood cell counts
  • Swelling of the mouth lining
  • Weight loss
  • Upper respiratory tract infections
  • Fever
  • Low platelet counts
  • Swelling of the mucous membranes
  • Swelling of the nose and throat
  • Change in sense of taste

These symptoms usually appear within 24 hours of receiving Herceptin.

If you have an allergic reaction to this drug, call your doctor right away. Allergy symptoms include:

  • Extreme shortness of breath
  • Wheezing
  • Swelling of throat or lips
  • Hives


Herceptin comes with a few risks to consider.

First, it can cause heart problems and congestive heart failure. Your left ventricular function needs to be checked immediately before starting Herceptin, at regular time intervals while on it (package insert recommendation is every 3 months), and after you finish treatment. 

The risk of heart problems increases if you are being treated with Adriamycin and Cytoxan as well as Herceptin.

Do not take Herceptin if you are pregnant or breastfeeding.

Use contraception while in treatment with Herceptin, because this drug may cause harm to the baby if you conceive. If you're already pregnant, be sure to tell your doctor.

Use contraception while in treatment with Herceptin, because this drug may cause harm to the baby if you conceive. If you're already pregnant, be sure to tell your doctor.

Most oncologists recommend that you avoid alcohol, tobacco, or caffeine during Herceptin treatment.

Caffeine causes drying of your tissues, which only adds to the drying effects already caused by your chemo drugs.

Tell your healthcare team if you are using tobacco, alcohol, or recreational drugs, and, if necessary, ask for help in quitting.


Taking good care of yourself, in general, is important to your health and well being. During treatment, you should be sure to save time for self-care.

  • Stay well-hydrated by drinking two or three quarts of fluids every 24 hours
  • If needed, take your anti-nausea medications as directed
  • If you're dizzy or drowsy, take it easy until these symptoms subside
  • If you have flu-like symptoms, pile on the blankets and drink lots of fluids (sports drinks can help)
  • Aches and pains may be relieved with acetaminophen or ibuprofen, but check with your doctor first
  • Rest as much as you can
  • Eat a good, nutritious diet
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