Suzie,
The below is from the Mayo Clinic website:
HER2-positive breast cancer is a breast cancer that tests positive for a protein called human epidermal growth factor receptor-2 (HER2), which promotes the growth of cancer cells. In about one of every three breast cancers, the cancer cells make an excess of HER2 due to a gene mutation. This gene mutation can occur in many types of cancer — not only breast cancer.
HER2-positive breast cancers tend to be more aggressive than other types of breast cancer.
They're also less responsive to hormone treatment. However, new treatments that specifically target HER2 are proving to be very effective:
- <LI class=doublespace>Trastuzumab (Herceptin). Herceptin, which specifically targets HER2, kills these cancer cells and decreases the risk of recurrence. Herceptin is often used with chemotherapy. But it may also be used alone or in combination with hormone-blocking medications, such as an aromatase inhibitor or tamoxifen. A study published in 2005 found that Herceptin can reduce breast cancer recurrence by as much as 50 percent. Herceptin is usually well tolerated, but it does have some potential side effects, such as congestive heart failure and allergic reaction. This drug is also very expensive. <LI class=doublespace>Lapatinib (Tykerb). Like Herceptin, Tykerb is a HER2-specific drug. Approved by the Food and Drug Administration in 2007, Tykerb may be effective for HER2-positive breast cancer that doesn't respond to Herceptin. Tykerb is used in combination with the chemotherapy drug capecitabine (Xeloda).
- Certain chemotherapy regimens, such as combinations of anthracycline drugs — doxorubicin (Adriamycin), epirubicin (Ellence).
Breast tissue can be tested for HER2, and routine testing is recommended for most women with breast cancer because the results may affect treatment recommendations and decisions. Whenever breast cancer recurs or spreads, the cancer cells should be tested for HER2.
