SALT LAKE CITY – Women who resumed menstruating after undergoing chemotherapy for breast cancer usually recovered about half their ovarian reserve 13 months later, according to interim results from a prospective cohort study.
“These findings provide important references for counseling patients before chemotherapy about their expectations for ovarian recovery. Patients who were not able to freeze enough oocytes before chemotherapy can expect to be able to stimulate approximately half as many for cryopreservation post chemo,” Joseph Letourneau, MD, and his colleagues at the University of California, San Francisco wrote in a poster presented at the annual meeting of the American Society for Reproductive Medicine.
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Chemotherapy increases the risk of infertility and early menopause. But in past studies, some 70% to 80% of women regained at least some level of ovarian function after completing treatment, the researchers noted. Over the course of 6-12 months, quiescent follicles mature to the antral stage, in which exposure to follicle-stimulating hormone triggers their rapid growth and maturation. Thus, antral follicle count is an accepted marker of ovarian reserve that reliably predicts how many oocytes will be retrieved during in vitro fertilization and fertility preservation, according to the investigators.
Based on these observations, they tracked antral follicle counts over time among 199 patients who were seen for fertility preservation consultations before starting cyclophosphamide-based chemotherapy for breast cancer, and who resumed menstruating afterward. Before chemotherapy, these women had an average antral follicle count of 15, with a standard deviation of 12. They averaged 35 years of age, with a standard deviation of 5 years.
A total of 66 women returned after chemotherapy for follow-up, and underwent an average of four antral follicle counts, with a standard deviation of two, the researchers said. These measurements showed that for up to 12 months after finishing chemotherapy, patients typically had only about 14% to 25% of their baseline ovarian reserve. By month 13, however, antral follicle counts rose to an average of 52% of baseline, and remained at this level through month 18 and beyond.
Treatment with leuprolide during chemotherapy appeared to increase ovarian recovery from about month 7 onward, the researchers reported. Between 7 and 9 months after chemotherapy, antral follicle counts averaged 32% of baseline among patients who had received leuprolide, but were about 8% of baseline among patients who had not received leuprolide. Between months 13 and 18, leuprolide recipients recovered about 74% of their ovarian reserve, while other patients recovered about 35% (P = .09). Beyond month 18, leuprolide recipients recovered an average of 69% of their baseline antral follicle count and other patients recovered an average of 4 (P = .07).
“Women who did not take [leuprolide] during chemotherapy represent 75% of our study population,” the researchers said. “[These women] appeared to have lower antral follicle count recovery, despite resumption of menses, than those whose menses resumed after chemotherapy with concurrent [leuprolide].”
Dr. Letourneau reported having no relevant financial disclosures.