NEW YORK (Reuters Health) – Results of a study suggest that gonadotropin-releasing hormone (GnRH) agonist therapy does not help preserve ovarian function in young women undergoing modern chemotherapy for early breast cancer.

GnRH agonist therapy “should not be recommended” for this purpose,” Dr. Pamela Munster from University of California, San Francisco and colleagues conclude in a paper online in the Journal of Clinical Oncology.

The author of a linked commentary agrees.

“Given the current level of evidence, women who are interested in future fertility and the providers who are assisting them in these often difficult decisions should not rely on GnRH agonist treatment during chemotherapy for preservation of menstrual and ovarian function or fertility,” writes Dr. Ann Partridge, of the Dana-Farber Cancer Institute and Brigham and Women’s Hospital, Boston.

The use of these agents is “appealing” relative to alternative strategies of in vitro fertilization and embryo cryopreservation before treatment, Dr. Partridge points out.

Several uncontrolled studies have suggested that giving a GnRH agonist during chemotherapy may decrease the incidence of amenorrhea, but overall available data are mixed.

In a prospective randomized trial, Dr. Munster and colleagues tested the GnRH agonist triptorelin (versus no triptorelin) for preservation of ovarian function during adjuvant or neoadjuvant modern breast cancer chemotherapy.  They had planned to enroll 124 women aged 44 years or younger, but the trial was stopped for futility after 49 women were enrolled.

According to the investigators, after a median follow-up of 18 months, menses returned in 23 of the 26 women in the triptorelin arm (88%) and 19 of 21 women in the control arm (90%). The difference was not significant (P = 0.36).

There was also no difference in the time to return of menses between the two groups (median of 5.8 months in the triptorelin group and median of 5.0 months in the control group; P = 0.58).

In an email to Reuters Health, Dr. Munster said this study shows that “the newer shorter duration types of chemotherapy do not induce menopause in over 80% of women.”

“Earlier studies have shown that the short term suppression of ovarian function preserves menstruation. Our study does not show this; what we find is that there are much fewer women going into menopause from chemotherapy than in those earlier studies and hence there is not drastic difference in the outcomes. In fact, two women in the control group became pregnant spontaneously,” Dr. Munster noted.

In her commentary, Dr. Partridge says based on this “well-conducted” study, as well as two additional negative trials (the ZORO trial and the OPTION trial) and two other conflicting reports, “the role of ovarian suppression through chemotherapy remains uncertain for prevention of premature menopause.”

Dr. Munster cautioned, however, that not undergoing menopause does not guarantee that patients retain their fertility.  “Women who wish to conceive should see a fertility specialist before they start chemotherapy. New technologies in egg and oocytes freezing may be an alternative to preserve the ability to have a biological child,” she noted.

SOURCE:

Randomized Trial Using Gonadotropin-Releasing Hormone Agonist Triptorelin for the Preservation of Ovarian Function During (Neo)Adjuvant Chemotherapy for Breast Cancer

J Clin Oncol. 2012.