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What Happens During Targeted Therapy for Breast Cancer

Herceptin (trastuzumab) is one of a group of drugs used in targeted therapy. Tykerb (lapatinib) and Perjeta (pertuzumab) are others that may be used to treat breast cancer. These drugs target a certain protein called HER2/neu (or  HER2), which is found in larger than normal amounts on the surface of the breast cancer cells in most people. These targeted drugs can help slow the growth of these breast cancers.

Herceptin and Perjeta are given through an intravenous (IV) injection into your vein. It will take 30 to 90 minutes to get your full dose. You can usually have this done as an outpatient.

Tykerb is given as a pill that you take at home in two- or three-week cycles. It is taken once a day at least one hour before or one hour after a meal. 

Targeted therapy drugs work differently from standard chemotherapy drugs. Because they target particular cells, they tend to be less damaging to healthy cells than other types of treatment and usually have less severe side effects. Ask your doctor which side effects you are most likely to experience. Here is a list of possible side effects:

  • Chills

  • Diarrhea

  • Fever

  • Headaches

  • Nausea

  • Rashes

  • Trouble breathing

  • Vomiting

  • Weakness

If you have trouble breathing, leg swelling, or feel extremely tired, call your doctor right away. A possible serious side effect of these drugs is heart damage that may lead to congestive heart failure. For many women, this is a short-term problem that gets better when the drug is stopped. It appears that the risks for heart problems are higher when certain chemotherapy drugs are given along with the more common targeted therapies used for breast cancer. 

You may find that most side effects are less severe after your first treatment. They usually go away or get better within a few weeks after your treatment ends. If you're having uncomfortable side effects, tell your doctor or nurse so that he or she can help you manage them. 


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