Types of Breast Cancer: ER Positive, HER2 Positive, and Triple Negative
HER2-Positive Breast Cancer continued...
For women with HER2-positive breast cancers, the drug Herceptin has been shown to dramatically reduce the risk of recurrence. It has now become standard treatment to give Herceptin along with adjuvant (after-surgery) chemotherapy in those with metastatic breast cancer. Another drug, Tykerb, is often given for metastatic cancer if Herceptin fails. Kadcyla is another drug that can be given after Herceptin and a class of chemotherapy drugs called taxanes, which are commonly used to treat breast cancer.
Herceptin has far fewer immediate side effects than chemotherapy -- for example, there is usually no nausea or hair loss. However, there is a small but real risk of heart damage and possible lung damage. Scientists are still studying how long women should take Herceptin for the greatest benefit.
An intravenous treatment called Perjeta is also approved for late-stage HER2-positive breast cancer. In one study, Perjeta was shown to extend life when given in combination with Herceptin.
Triple-Negative Breast Cancer
Some breast cancers -- estimates range between 10% and 17% -- are known as “triple negative” because they lack estrogen and progesterone receptors and do not overexpress the HER2 protein. The majority of breast cancers associated with the breast cancer gene known as BRCA1 are triple negative.
These cancers generally respond well to adjuvant chemotherapy. Overall, however, they have a poorer prognosis than other types of breast cancer. So far, no targeted therapies like tamoxifen or Herceptin have been developed to help prevent recurrence in women with triple-negative breast cancer. Cancer experts are studying several promising targeted strategies aimed at triple-negative breast cancer.