Breast Cancer Health Center
Hormone Therapy for Breast Cancer
About two-thirds of women with breast cancer have tumors that contain estrogen receptors (called ER-positive). This type of cancer depends on the female hormone to grow. Hormone therapy is given to block the body's naturally occurring estrogen and fight the cancer's growth. Women who are ER-positive are more likely to respond to hormone treatment than women who are ER-negative.
Tamoxifen for Breast Cancer
Tamoxifen is a pill taken daily and has been used consistently for the past decade to treat breast cancer. Tamoxifen can be used in women of any age, regardless of whether they've gone through menopause. Long-term (five-year) use of this anti-estrogen drug has been found to reduce the chance of breast cancer recurrence and new breast cancers in women with ER-positive or ER-unknown breast tumors. Doctors also use tamoxifen to treat metastatic breast cancer. There is no advantage in taking tamoxifen for more than five years.
Women taking tamoxifen are more likely to develop cancer of the uterus (endometrial cancer) than other women. Therefore, they should have regular pelvic exams and tell their doctor about any abnormal uterine bleeding. Other risks include deep-vein thrombosis, blood clots in the lungs, and benign ovarian cysts. Minor side effects include hot flashes, mood swings, and cataracts.
Aromatase Blockers and Breast Cancer
Aromatase blockers are pills that appear to be more effective in treating breast cancer than tamoxifen, according to new studies. But they are effective only in women who are past menopause. Aromatase blockers - used in both early and advanced breast cancer - prevent estrogen from being produced in the first place. They inhibit or inactivate the aromatase enzyme, which is involved in the production of estrogen.
Arimidex (anastrozole) and Femara (letrozole) are aromatase blockers used to treat estrogen receptor positive breast cancer in postmenopausal women, either following tamoxifen treatment or as first line therapy. A 2008 study showed that women taking Femara reduced their risk of their cancer returning by 63%. That's several years after completing the recommended five years on tamoxifen.
Positive results have also been demonstrated with Arimidex. One study found that switching to Arimidex after 2 to 3 years of tamoxifen was linked to better survival without disease recurrence at the 5-year mark compared with staying on tamoxifen for 5 years.
A third pill, Aromasin (exemestane), is used for women with early breast cancer after 2 to 3 years of tamoxifen treatment. In clinical research, compared to women that continued tamoxifen for 5 years, women who switched to Aromasin after 2 to 3 years of tamoxifen had a 31% lower risk of breast cancer recurrence and a 14% decrease in mortality.
Aromasin is also used for women with advanced breast cancer when tamoxifen stops working. It is only used in women after menopause.
WebMD Medical Reference
VIVELLE-DOT (estradiol transdermal system) IS AVAILABLE BY PRESCRPTION ONLY.
INDICATION
Vivelle-Dot is used after menopause to: reduce moderate to severe hot flashes; treat moderate to severe dryness, itching and burning in or around the vagina; help reduce your chances of getting osteoporosis (thin weak bones); and treat certain conditions in which a young woman's ovaries do not produce enough estrogens naturally. Vivelle-Dot 0.025 mg/day is only used to prevent osteoporosis from menopause. If you use Vivelle-Dot only to treat your dryness, itching, and burning in and around your vagina or if you use Vivelle-Dot only to prevent osteoporosis from menopause, talk with your healthcare professional about whether a different treatment or medicine without estrogens might be better for you.
IMPORTANT SAFETY INFORMATION
Estrogens increase the chances of getting cancer of the uterus (womb). Report any unusual vaginal bleeding right away while you are taking estrogens. Vaginal bleeding after menopause may be a warning sign of cancer of the uterus (womb).
Do not use estrogens with or without progestins to prevent heart disease, heart attacks, or strokes. Using estrogens with or without progestins may increase your chances of getting heart attacks, strokes, breast cancer, and blood clots. Using estrogens with progestins may increase your risk of dementia (decline in memory and thinking skills).
Vivelle-Dot should not be used if you have unusual vaginal bleeding; currently have or have had certain cancers, including cancer of the breast or uterus; had a stroke or heart attack in the recent past (for example, in the past year); currently have or have had blood clots; currently have or have had liver problems; or think you may be, or know that you are, pregnant.
The most common side effects that may occur with Vivelle-Dot are headache, breast tenderness, and back pain.
You and your healthcare professional should talk regularly about whether you still need treatment with Vivelle-Dot.
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.
Please see Full Prescribing Information for Vivelle-Dot.

