Chemotherapy is often used to treat breast cancer in both premenopausal and postmenopausal women. In premenopausal women, chemotherapy can disrupt normal ovary function and cause damage, which leads to either temporary or permanent menopause and infertility. This is called chemotherapy-induced menopause.
An Italian study found that women who got the medicine triptorelin (brand name: Trelstar) during chemotherapy treatment for breast cancer were much less likely to develop chemotherapy-induced menopause compared to women who didn't get triptorelin during chemotherapy. The results were published in the July 2011 issue of the Journal of the American Medical Association.
Triptorelin is a type of medicine called a gonadotropin hormone-releasing hormone (GnRH) agonist or a luteinizing hormone-releasing hormone (LHRH) agonist. These medicines work by telling the brain to tell the ovaries to stop making estrogen. Zoladex (chemical name: goserelin) and Lupron (chemical name: leuprolide) are other examples of this type of medicine. Zoladex and Lupron are more commonly used in the United States, while triptorelin is more commonly used in Europe.
The ovaries of premenopausal women usually make a lot of estrogen. In premenopausal women diagnosed with hormone-receptor-positive breast cancer, estrogen can promote the growth and spread of the cancer. So doctors sometimes recommend that these women have their ovaries removed (prophylactic ovary removal) as part of the overall breast cancer treatment plan. Removing the ovaries reduces the risk of the cancer coming back. Because prophylactic ovary removal permanently removes the primary source of estrogen, women who undergo it are immediately thrown into menopause.
Triptorelin, Zoladex, and Lupron are alternatives to prophylactic ovary removal -- especially for women who may want to get pregnant later. One of the medicines may be prescribed for a period of time after breast cancer surgery to temporarily turn off estrogen production by the ovaries. This is called medical ovarian shutdown. The medicines are given as injections once a month for several months or every few months. Once the medicine is stopped the ovaries may begin to function again, as long as chemotherapy didn't permanently damage them. The time it takes for the ovaries to recover is different for each woman.
In this study, all the women had been diagnosed with early-stage breast cancer and all of them were scheduled to get chemotherapy either before or after breast cancer surgery. Half the women were randomly chosen to get triptorelin injections starting a week before chemotherapy started and continuing as long as chemotherapy did. The other women didn't get triptorelin during chemotherapy.
After chemotherapy was done, women diagnosed with hormone-receptor-positive breast cancer got tamoxifen for 5 years to reduce the risk of the cancer coming back. Tamoxifen is given to reduce the risk of cancer coming back in both premenopausal and postmenopausal women diagnosed with early-stage hormone-receptor-positive breast cancer. Tamoxifen, a pill taken by mouth, works by blocking estrogen's effects on breast cancer cells.
Women diagnosed with hormone-receptor-positive breast cancer who had started menstruating again got triptorelin every 4 weeks for at least 2 years, also to reduce the risk of the cancer coming back. These women got triptorelin whether or not they got triptorelin during chemotherapy.
Women who got triptorelin during chemotherapy were much less likely to have chemotherapy-induced menopause compared to women who didn't get triptorelin during chemotherapy:
- 25.9% of women who didn't get triptorelin during chemotherapy had chemotherapy-induced menopause.
- 8.9% of women who got triptorelin during chemotherapy had chemotherapy-induced menopause.
It's important to know that even though the study found that menstruation was more likely to return if a woman got triptorelin during chemotherapy, the researchers didn't look at whether fertility after chemotherapy was also more likely.
The researchers think that shutting down the ovaries during chemotherapy might protect them from chemotherapy damage and so make chemotherapy-induced menopause less likely in premenopausal women getting chemotherapy.
If you're a premenopausal woman diagnosed with early-stage breast cancer and chemotherapy will be part of your treatment plan, you might want to talk to your doctor about this study and whether a medicine like triptorelin during chemotherapy makes sense for you.
Whether or not you get a medicine like triptorelin during chemotherapy, your doctor may recommend medical ovarian shutdown or prophylactic ovary removal after breast cancer surgery to reduce the risk of the cancer coming back. You can learn more in the Breastcancer.org Prophylactic Ovary Removal pages.