Hormonal and Other Therapies
If your breast cancer is hormone-positive, your doctor may recommend that you have hormonal therapy, typically in addition to or following other types of treatment.
“Hormone-positive” means that your cancer has the receptors for the hormones estrogen or progesterone. The majority of women with breast cancer have hormone receptor positive (HR+) disease.
If your cancer is not hormone positive, you will not benefit from hormonal therapy.
Other therapies used in breast cancer treatment include:
• Tamoxifen
• Arimidex
• Monoclonal antibodies (Herceptin)
• Tyrosine kinase inhibitors (Lapatinib)
Hormonal Therapies
The two most common hormonal therapies used to treat breast cancer are anti-estrogens such as Nolvadex (generic, tamoxifen), and the aromatase inhibitors such as Arimidex (generic, anastrazole), Femara (letrozole), and Aromasin (exemestane). All are pills that are taken daily by mouth.
• Tamoxifen is indicated for premenopausal women.
• Aromatase inhibitors or tamoxifen are indicated for postmenopausal women.
Aromatase inhibitors block an enzyme in cells, and prevent estrogen from being made by cells from other hormones. However, aromatase inhibitors do not block production of estrogen from the ovaries, hence they are ineffective, and potentially harmful, in premenopausal women.
There are also alternative hormonal treatments that may be used for women with advanced, or metastatic, breast cancer. These include fulvestrant (brand name, Faslodex) and DES, or diesthystilbestrol, which is sometimes used to treat women with metastatic breast cancer that has not responded to other hormonal therapies.
Systemic Therapy
Like chemotherapy, hormonal therapy is a "systemic" therapy, one that circulates in the bloodstream to attack cancer cells throughout the body.
Hormonal therapy works because estrogen and other hormones affect the growth of breast cancer cells. Reducing or stopping hormone production helps prevent the growth of cancer cells in women whose cancers are hormone receptor-positive.
A woman with breast cancer whose cancer is hormone receptor-positive may have hormonal therapy following other treatments, such as surgery, chemotherapy, and radiation. This therapy reduces the risk of a recurrence of breast cancer and also reduces the risk of a new breast cancer.
Monoclonal Antibodies
Monoclonal antibody therapy uses antibodies that can identify substances on cancer cells or normal substances that may help cancer cells grow. These antibodies attach to the substances and kill the cancer cells, block their growth, or keep them from spreading. Monoclonal antibodies are given by infusion and may be used alone or to carry medications or radioactive material directly to cancer cells. Monoclonal antibodies are also used in combination with chemotherapy as adjuvant therapy.
Herceptin a targeted therapy that attacks cancer cells that "over-express," or make too much of, a protein called HER2. It is a monoclonal antibody that blocks the effects of the HER2 protein that transmits growth signals to breast cancer cells. About 20 to 25 percent of women with breast cancer have tumors that may be treated with herceptin combined with chemotherapy.
Side Effects
Because it is a targeted treatment that only attacks cancer cells, the side effects are milder than those of conventional chemotherapy, which attacks all fast-growing cells. However, the side effects of Herceptin do include an increased risk of heart problems, including congestive heart failure.
New research
As a result of new research studies, doctors have begun to use Herceptin to treat women who have been newly diagnosed with HER2-positive breast cancer. Herceptin is recommended for these women as an adjuvant (post-surgery) treatment in combination with chemotherapy.
Three new research studies on the use of Herceptin to treat women with early-stage, HER2-positive breast cancer found that the drug was very effective in keeping these women’s cancer from returning. In fact, it cut the risk of recurrence of this aggressive type of breast cancer in half.
Tyrosine Kinase Inhibitors are drugs that block signals needed for tumors to grow. Tyrosine kinase inhibitors may be used in combination with other anticancer drugs as adjuvant therapy. Lapatinib is a tyrosine kinase inhibitor that blocks the effects of the HER2 protein and other proteins inside tumor cells. It may be used to treat patients with HER2-positive breast cancer that has progressed following treatment with herceptin.