Herceptin Therapy for Breast Cancer

For HER2-positive and metastatic breast cancer

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Herceptin (trastuzumab) is a chemotherapy infusion medication approved for metastatic breast cancer and as an adjuvant treatment for HER2-positive breast cancer. The drug is essentially a protein that targets and binds to the human epidermal growth factor receptor2 (HER2) protein to impede cancer cells from proliferating further.

HER2 is an aggressive form of breast cancer that grows and spreads rapidly. About one in five women with breast cancer have HER2-positive breast cancer or protein human epidermal growth factor receptor2.


For HER2-positive breast cancer, Herceptin is used as an adjuvant chemotherapy treatment, meaning that it follows primary treatment, which is usually surgery. It's considered effective for early-stage HER2-positive breast cancer regardless of whether it has 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.

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.

 Verywell / Gary Ferster

How It Works

The HER2 gene generates a protein receptor on the surface of a tumor cell. This receptor signals the cell to divide and multiply. When there's too much HER2 in breast cancer tissue, cell division ramps up.

Herceptin attaches to the HER2 receptors and blocks that growth signal, preventing more cell division and slowing the progression of cancer. The drug only hunts down those cancer cells that have HER2/neu receptors on their outer surface.

Herceptin is part of a class of drugs called biologic therapies.


Herceptin is a pale white or yellow fluid that's given via 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 an allergic reaction.

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 have reported the following side effects: 

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

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

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

Some patients receiving Herceptin for metastatic stomach cancer had the following additional side effects, which should also be considered:

  • Swelling of the mouth lining
  • Weight loss
  • Upper respiratory tract infections
  • 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 the infusion.


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 (the package insert recommendation is every three 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.

Most oncologists recommend that you refrain from using alcohol and tobacco during Herceptin treatment. Caffeine should also be avoided, as it 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 quitting.

Do not take Herceptin if you are pregnant or breastfeeding. Use contraception while being treated with Herceptin, as this drug may cause harm to the baby. If you're already pregnant, be sure to tell your healthcare provider.


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, stay warm and drink lots of fluids (sports drinks can help).
  • Aches and pains may be relieved with acetaminophen or ibuprofen, but check with your healthcare provider first.
  • Rest as much as you can.
  • Eat a good, nutritious diet.
4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Cancer Society. Targeted Therapy for Breast Cancer. Revised September 18, 2019.

  2. Cameron D, Piccart-gebhart MJ, Gelber RD, et al. 11 years' follow-up of trastuzumab after adjuvant chemotherapy in HER2-positive early breast cancer: final analysis of the HERceptin Adjuvant (HERA) trial. Lancet. 2017;389(10075):1195-1205.

  3. Breastcancer.org. Herceptin. Revised September 27, 2019

  4. Chemocare.com. Herceptin.

Additional Reading

By Pam Stephan
Pam Stephan is a breast cancer survivor.