Targeted Therapy


What is targeted therapy?

In addition to systemic chemotherapy and hormone therapy, there are newer, more effective treatments that can attack specific breast cancer cells without harming normal cells. Currently, these targeted methods are commonly used in combination with traditional chemotherapy. However, targeted drugs often have less severe side effects than standard chemotherapy drugs.

How do breast cancer targeted therapies work?
Breast Cancer Targeted therapy uses drugs that block the growth of breast cancer cells in specific ways. For example, targeted therapy may block the action of an abnormal protein (such as HER2) that stimulates the growth of breast cancer cells.

Trastuzumab (Herceptin®) or lapatinib (TYKERB®) may be given to a woman whose lab tests show that her breast tumor has too much HER2.

Monoclonal Antibodies: Binding agents for cancer cells

One type of targeted therapy currently being studied is monoclonal antibodies. These laboratory-manufactured proteins bind with certain cancers.

Herceptin or Trastuzumab

Monoclonal antibody drugs such as Herceptin (also known as trastuzumab) and Lapatinib target HER2-positive tumors. If cancer cells are positive for the HER2/neu receptors that means there is an overabundance of receptors on the cancer cell for the growth-stimulating HER2 protein.

The tumor acts almost like a magnet for growth hormones, and when the tumor cells connect with growth hormone cells, the cancer can quickly grow and multiply. Herceptin helps shrink these HER2-positive tumors by finding the cells, binding with them, and blocking the action of the receptor.

How is Trastuzumab administered and what are the likely side effects?

This drug is given through a vein. It may be given alone or with chemotherapy. Side effects that most commonly occur during the first treatment include fever and chills.

Other possible side effects include weakness, nausea, vomiting, diarrhea, headaches, difficulty breathing, and rashes. These side effects generally become less severe after the first treatment. Trastuzumab also may cause heart damage, heart failure, and serious breathing problems. Before and during treatment, your doctor will check your heart and lungs.

Bevacizumab: Reducing the cancer cells’ blood supply

Another targeted therapy, Bevacizumab, prevents tumors from making new blood vessels that could feed the tumor, essentially cutting off the cancer cells from all nutrients.

Lapatinib: blocking abnormal proteins that signal cancer cells to multiply

This tablet, taken by mouth, helps stop or slow the spread of cancer cells. Lapatinib is given with chemotherapy or after other methods have not worked to slow the cancer.

Side effects can include nausea, vomiting, diarrhea, tiredness, mouth sores, and rashes. It can also cause red, painful hands and feet. Before treatment, your doctor will check your heart and liver. During treatment, your doctor will watch for signs of heart, lung, or liver problems.

As with all medical treatments, if you experience unusual changes in your health during targeted therapy, notify your doctor immediately.


Material on this page courtesy of the National Cancer Institute

Need Support?

Join the MyNBCF, a support community for breast cancer patients, survivors and their loved ones to discuss diagnosis, treatment and everything in between.

Have Breast Cancer Questions?

Get answers at, our educational resource.

Hear Survivor Stories

Listen to stories from breast cancer survivors as they talk about their diagnosis, treatment and everything in between on