ASCO Breast Study Focuses on Preserving Fertility in Young Women
Results of a long-term follow-up study of a phase III clinical trial, PROMISE-GIM6 (Prevention of Menopause Induced by Chemotherapy: A Study in Early Breast Cancer Patients), show pregnancy was more than twice as likely to occur over a 7-year period in young women who took triptorelin (Trelstar).
Triptorelin is a hormone-targeting medicine that is FDA approved to treat symptoms of advanced prostate cancer and is under study in breast cancer.
Matteo Lambertini, MD, an oncology fellow at San Martino-IST in Genova, Italy, announced findings during the American Society of Clinical Oncology 2014 Breast Cancer Symposium on September 4.
Chemotherapy can affect your fertility by damaging follicles, the egg-containing sacs, in the ovaries. This reduces the number of eggs and shortens the amount of time you will be fertile if your periods return.
Risk of ovarian failure, loss of normal function of your ovaries before age 40, depends on the kind of chemotherapy you receive, and the amount. Age, and possibly the timing of the menstrual cycle, the time during the month that eggs develop in the ovaries, at the time of chemotherapy may also be factors. You may stop having your period temporarily or permanently because of the loss of eggs in your ovaries, or experience early menopause with hot flashes and other side effects.
Hormonal medicines called GnRH or LHRH agonists are being explored to protect ovaries from the harsh effects of chemotherapy so they can recover more fully and quickly. These medicines shut down, or suppress, your ovaries, and cause menopausal symptoms for as long as you take them.
Initial results of PROMISE-GIM6 were published in the Journal of the American Medical Association, JAMA, in 2011. They showed that temporarily suppressing the ovaries with triptorelin during chemotherapy treatment reduced the occurrence of early menopause in young women with early-stage breast cancer. Women who received chemotherapy combined with triptorelin became pregnant more often than women treated with chemotherapy alone.
Still, the 2013 ASCO and European Society for Medical Oncology (ESMO) guidelines on preserving fertility in people diagnosed with cancer consider this approach experimental because there is not enough data on long-term ovarian function and pregnancy rates. There are also some concerns that this procedure might not be safe, particularly for people with hormone-receptor positive breast cancer.
This analysis reports results of a long-term follow-up of the trial.
PROMISE-GIM6 focused on 281 premenopausal women with stage I to III breast cancer who could have chemotherapy. Participants were randomly assigned to one of two groups: the first, 148 people, received chemotherapy with the GnRH agonist triptorelin while the second, 133 people, received chemotherapy alone.
After roughly 7 years of follow-up, three pregnancies occurred in the chemotherapy alone group and eight in the combined therapy group. In the chemotherapy alone group, 96 women started having periods again, compared with 116 in the combined therapy group. Researchers found no differences in the 5-year breast cancer-free survival between the groups.
What This Means For You
In a follow-up presentation, Hope Rugo, MD, professor of medicine in the division of hematology and oncology at the University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, said that this treatment is not a substitute for established methods of fertility preservation such as freezing eggs and embryos.
Dr. Lambertini also cautioned that although the data is reassuring in terms of safety, 7 years is not long enough to say that the procedure is absolutely safe.
If you are a premenopausal woman who has been diagnosed with breast cancer, talk to your doctor about fertility options before starting treatment. Learn more about fertility options in our Young Women's Initiative section.