Before and during chemotherapy, giving premenopausal women with estrogen receptor-negative (ER-) breast cancer the medicine goserelin (Zoladex) improved their ability to become pregnant several years after treatment and to deliver healthy babies.
These results, from a small study of women with early-stage, ER- breast cancer, were presented as late-breaking news at the American Society of Clinical Oncology’s annual meeting. They were later published in the New England Journal of Medicine, in March 2015.
Background and Reason for the Study
Chemotherapy affects the whole body. It is known to damage ovarian follicles, which hold eggs vital to the reproductive process. After receiving chemotherapy, premenopausal women typically have an early menopause, as their ovaries stop working years before women of the same age who have not had chemotherapy. Because of this, some women treated with chemotherapy may be unable to become pregnant.
Goserelin, a luteinizing hormone-releasing hormone (LHRH) analog, also known as a gonadotropin-releasing hormone (GnRH) agonist,stops the ovaries from working for a limited time. It holds back hormone production, causing temporary menopause. If given during chemotherapy, this may protect ovarian follicles from damage.
LHRH analog medicines have been studied for their ability to protect fertility during chemotherapy, but results have been mixed or inconclusive. Many of those studies used the return of menstruation as proving healthy ovarian function, although having periods does not necessarily indicate a woman will be able to become pregnant in the future. Prior studies also have not shown LHRH analogs help women’s ability to carry pregnancies to term (birth) following chemotherapy for breast cancer.
The researchers wanted to find out if using goserelin with chemotherapy would protect the ovaries from permanent damage, called ovarian failure, or affect pregnancy outcomes afterward.
The Prevention of Early Menopause Study, POEMS, included premenopausal women with stage I-IIIA, hormone receptor-negative breast cancer. Participants were randomly assigned to treatment groups. All were given standard chemotherapy; some also received goserelin. Goserelin was first given at least 1 week before chemotherapy began, then every 4 weeks during chemotherapy treatment.
The women in both groups were evaluated for ovarian failure at 2 years. For this study, ovarian failure meant the woman had had no monthly periods for the past 6 months and had postmenopausal levels of follicle-stimulating hormone (FSH), which affects reproductive ability. Data was also gathered about whether women who tried to become pregnant after treatment succeeded, how many babies were born, and the women’s overall survival with or without cancer recurrence.
Data for evaluation was available for
- 69 of 131 women – chemotherapy alone group
- 66 of 126 women – goserelin with chemotherapy group
Some women didn’t have lab tests at the end of the study, so their data could not be used.
At 2 years, the study found that the goserelin group did better than the chemotherapy only group in
- ovarian failure rate
- 8 percent compared with 22 percent – a 70 percent reduction
- becoming pregnant after treatment
- 22 of 25 women who tried to become pregnant succeeded, compared with 12 of 18
- 18 babies born to 16 women compared with 12 babies born to 8 women
This study had few participants, and 38 percent of participants had missing data. The study also closed early. Due to the small number of women in the study, improved survival found in the goserelin group needs more investigation.
Additional research is needed, but adding goserelin to chemotherapy is one option to consider if you have hormone receptor-negative breast cancer. Researchers believe goserelin may prove to be useful as well for hormone receptor-positive disease, a more common breast cancer profile, but that also needs further research.
What This Means for You
Before beginning treatment, talk with your medical oncologist about these study results if you are concerned about future pregnancy. Ask whether adding goserelin to chemotherapy might be right for you.
There are other ways to preserve your fertility and improve your chances of becoming pregnant after treatment ends. Talk with a fertility specialist to find out about your options before treatment or for advice if you have already had chemotherapy.
Moore, HCF, Unger, JM, Phillips, KA et al. Phase III trial (Prevention of Early Menopause Study [POEMS]-SWOG S0230) of LHRH analog during chemotherapy to reduce ovarian failure in early-stage, hormone receptor-negative breast cancer: an international Intergroup trial of SWOG, IBCSG, ECOG, and CALGB (Alliance). Presented at 50th Annual Meeting of the American Society of Clinical Oncology; May 30-June 2, 2014; Chicago, IL. Abstract LBA505.
This article was supported by Cooperative Agreement Number DP11-1111 from The Centers for Disease Control and Prevention. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention.