The American Society of Clinical Oncology (ASCO) has put out updated guidelines on using ovarian suppression along with standard hormonal therapy medicine after surgery for premenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer.
The guidelines were published online on Feb. 16, 2016 by the Journal of Clinical Oncology. Read “Adjuvant Endocrine Therapy for Women With Hormone Receptor-Positive Breast Cancer: American Society of Clinical Oncology Clinical Practice Guideline Update on Ovarian Suppression.”
ASCO is a national organization of oncologists and other cancer care providers. ASCO guidelines give doctors recommendations for treatments and testing that are supported by much credible research and experience.
Thomas Buchholz, M.D., of the University of Texas MD Anderson Cancer Center; Cliff Hudis, M.D., of Memorial Sloan-Kettering Cancer Center; Eric Winer, M.D., of the Dana-Farber Cancer Institute; and Jennifer Griggs, M.D., of the University of Michigan, are among the ASCO experts who updated the guidelines. All four are members of the Breastcancer.org Professional Advisory Board.
After surgery, women diagnosed with early-stage, hormone-receptor-positive breast cancer usually take hormonal therapy medicine to reduce the risk of the cancer coming back (recurrence). Hormonal therapy given after surgery is called adjuvant hormonal therapy.
Hormonal therapy medicines work in two ways:
- by lowering the amount of estrogen in the body
- by blocking the action of estrogen on breast cancer cells
There are several types of hormonal therapy medicines. Tamoxifen, a selective estrogen receptor modulator (SERM), is one of the most well-known. Tamoxifen can be used to treat both premenopausal and postmenopausal women. The aromatase inhibitors:
- Arimidex (chemical name: anastrozole)
- Aromasin (chemical name: exemestane)
- Femara (chemical name: letrozole)
have been shown to be more effective at reducing recurrence risk in postmenopausal women and are now used more often than tamoxifen to treat women who’ve gone through menopause.
Aromatase inhibitors weren’t commonly used to reduce recurrence risk in premenopausal women. But a 2014 study, called the SOFT study, found that Aromasin plus ovarian suppression reduced recurrence risk more than tamoxifen plus ovarian suppression in premenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer who had been treated with chemotherapy. Ovarian suppression plus either type of hormonal therapy reduced recurrence risk more than tamoxifen alone after surgery for these women.
The updated ASCO guidelines offer doctors advice on which women should be offered ovarian suppression along with hormonal therapy after surgery.
For premenopausal women diagnosed with early-stage, hormone-receptor-positive breast cancer, the guidelines say:
- Women with stage II or stage III disease who would usually be treated with chemotherapy after surgery should be treated with ovarian suppression along with hormonal therapy after surgery.
- Women with stage I or stage II disease that has a higher risk of recurrence who might be treated with chemotherapy after surgery may be offered ovarian suppression along with hormonal therapy.
- Women with stage I disease that would not be treated with chemotherapy after surgery should be treated with hormonal therapy after surgery, but not ovarian suppression.
- Women with node-negative disease that is smaller than 1 cm should be treated with hormonal therapy after surgery, but not ovarian suppression.
- Ovarian suppression treatment should last for 5 years. While it’s recommended that some women take tamoxifen for 10 years, there hasn’t been enough research done to recommend ovarian suppression for more than 5 years.
- Ovarian suppression isn’t recommended for women who’ve been diagnosed with hormone-receptor-negative breast cancer.
- Tamoxifen, aromatase inhibitors, and ovarian suppression all may cause side effects, some of them severe. Tamoxifen may cause hot flashes and increase the risk of blood clots and stroke. Aromatase inhibitors may cause muscle and joint aches and pains, as well as hot flashes. Ovarian suppression also may cause hot flashes, mood swings, and lower libido. Women and their doctors should discuss the risks and benefits of any treatment being considered.
- The hormonal therapy given with ovarian suppression can be either tamoxifen or an aromatase inhibitor. Because each type of medicine has different side effects, a woman may prefer one type of hormonal therapy over the other.
If you’re a premenopausal women who has been diagnosed with early-stage, hormone-receptor-positive breast cancer and are deciding on treatments after surgery, you may want to ask your doctor about these updated guidelines.
Based on the characteristics of the cancer and your personal preferences, you will develop a treatment plan that includes hormonal therapy, and possibly ovarian suppression, that’s right for you and your unique situation.
While the side effects of hormonal therapy can be very severe for some women, they’re overshadowed by the reality that hormone-receptor-positive breast cancer can come back. Hormonal therapy after surgery reduces that risk. If side effects are a major problem for you, talk to your doctor about ways to manage them. Studies have shown that exercise and acupuncture may reduce hormonal therapy side effects. Visit the Breastcancer.org Staying on Track With Treatment pages to learn more about how to ease side effects.