Breast Cancer: Hormone Therapy Choices
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
Tamoxifen is a pill taken daily, and has been used consistently for the past decade. 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 Inhibitors
Aromatase inhibitors are pills that appear to be more effective than tamoxifen, according to new studies. But they are effective only in women who are past menopause. They prevent estrogen from being produced in the first place. There are three types of aromatase inhibitors that work in different ways on the same aromatase enzyme.
Anastrozole (Arimidex) and letrozole (Femara) are used to treat estrogen receptor positive breast cancer in postmenopausal women, either following tamoxifen treatment or as first line therapy. A Canadian study released in 2003 found that women who took Femara after a standard treatment of tamoxifen had a 43% reduction in Breast Cancer recurrence compared to women taking placebo. 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, exemestane (Aromasin), is used to treat advanced Breast Cancer in postmenopausal women who've already had standard anti-estrogen therapy.
For more information about hormone therapy, see Hormone Therapy for Breast Cancer from The Cleveland Clinic Foundation.
Also see, Follow-Up Care After Your Treatment.
Side Effects
Side effects of Armidex and Femara are rare. A serious side effect is the
possible development of osteoporosis. Bone density tests are used to monitor
for this condition.
If you have any of these side effects, contact your doctor right away:
- Nausea; vomiting; muscle or bone pain; fatigue; headache; dizziness; muscle weakness; swelling of the hands, feet, or lower legs; loss of appetite; constipation; diarrhea; abdominal pain; hot flashes; and cough.
Side effects of Aromasin include:
- Hot flashes, upset stomach, sweating and feeling tired or hungry.
kb120.com