Breast cancer:  What is Herceptin?

Breast cancer treatment often involves a targeted therapy called Herceptin. In this video I explain which breast cancer patients get Herceptin and what it is. This information is not intended as medical advice. Talk with your doctor before beginning any new health practice.

Transcript: 

Hello!  I’m Dr. Lisa Schwartz and this is Cancer Straight Talk where you get cancer information from a cancer doctor.  Today I’m going to be talking about a drug that is used very commonly in breast cancer called Herceptin.  The generic name is trastuzumab but since Herceptin is so much easier to say, that’s what I’m going to use today.

To understand what Herceptin is and how it treats breast cancer we need to first talk about proteins that appear on the surface of breast cancer cells.  There is a protein found on breast cancer cells that acts as a receptor called Human Epidermal Growth Factor Receptor-2 (HER2).  We test all breast cancers to see if they are HER2 positive (or overexpressing) or HER2 negative.  About 20% to 30% of invasive breast cancers overexpress the HER2 receptor (which makes them HER2 positive).  Having too many of these HER2 receptors can make the cancer grow and divide more rapidly which makes it more aggressive.

Herceptin is the medicine we use to treat breast cancers that overexpress HER2.  It is a “monoclonal antibody” that fits into the HER2 receptor and blocks its action preventing the rapid growth and division seen with HER2 positive cancers.  It also marks the cancer cell for destruction by your own immune system.  Monoclonal antibodies are produced in a laboratory but are designed to act like the antibodies produced by your own immune system when you are exposed to germs.  But these antibodies are designed to attach to one specific receptor.  In this case that is the HER2 receptor on breast cancer cells.

HER2 is overexpressed in other cancers as well and Herceptin is used to treat some of them.  There are also a few other drugs that are similar to Herceptin and target HER2 overexpression.

This type of therapy where we have pinpointed a receptor for the drug is called “targeted therapy.”  It tends to be less toxic than other types of chemotherapy because it is specific.  Herceptin does have some side effects though.  One of the most serious is its effect on heart function especially when it is used with another common type of chemotherapy for breast cancer called anthracyclines.  Your oncologist may recommend that you get an echocardiogram (which is an ultrasound of the heart) to measure your heart function at the beginning of your treatment and at various points during your treatment.  Some people can have reactions to the infusion of the drug including fevers and chills, nausea, vomiting, headache, and pain.  In general though, most patients feel that receiving Herceptin is a walk in the park especially if they have received other chemotherapy.

Herceptin is usually given weekly with other chemotherapy and then every 3 weeks by itself for one year.

So make sure you know whether or not your breast cancer overexpresses HER2.  Unless your cancer is very small, you will likely need to receive Herceptin.  I hope this has been helpful for you.  If you know someone else who may benefit from this information please feel free to share it.  Thanks for your time and attention and I’ll see you next time.  Take care and be well.