CHICAGO — A commonly used drug can help young women with breast cancer retain the ability to have babies, apparently protecting their ovaries from the damage caused by chemotherapy, researchers reported here on Friday.  The treatment could provide a new option for dealing with one of the painful dilemmas faced by young cancer patients — that doing the utmost to save their lives might impair or even ruin their fertility.  Researchers said the drug, goserelin, which temporarily shuts down the ovaries, appears to protect women from the more permanent premature menopause that can be induced by chemotherapy. In a clinical trial, women who were given goserelin injections along with chemotherapy had less ovarian failure and gave birth to more babies than women receiving only the chemotherapy.  “Premenopausal women beginning chemotherapy for early breast cancer should consider this new option to prevent premature ovarian death,” the study’s lead author, Dr. Halle Moore of the Cleveland Clinic, said at a news conference here at the annual meeting of the American Society of Clinical Oncology.  Dr. Ann H. Partridge, a breast cancer specialist at the Dana-Farber Cancer Institute in Boston and another author of the study, said about 16,000 American women under age 45 get breast cancer each year. Impaired fertility from chemotherapy is also a problem for women and men with other types of cancer and for children who survive the disease, though it is not clear if the results of this study would apply to them, she said.  Goserelin is sold by AstraZeneca under the brand name Zoladex. Global sales of the drug were about $1 billion in 2013.  Goserelin and similar drugs, known as gonadotropin-releasing hormone agonists, are commonly used as hormonal therapies to treat breast and prostate cancer. They are also used at fertility clinics to control the timing of ovulation.  The main option now for young breast cancer patients wanting to increase their chances of having babies is to have multiple eggs removed from their ovaries, as is done for in vitro fertilization. The eggs can be frozen or used to create embryos, which are then frozen.  But that is an invasive procedure and can cost $10,000 or more. And in some cases women have to start chemotherapy so quickly they do not have the two to three weeks needed to undergo the egg retrieval process.  Once-a-month injections of goserelin during chemotherapy could be a less expensive and easier alternative. In the study, each goserelin injection costs about $500 to $600, including the costs of giving the shot, said Dr. Kathy S. Albain of Loyola University Chicago, the senior author of the study. In the study, women typically needed four injections.  But until now, studies testing goserelin and similar drugs have reported inconsistent results. The oncology society’s guidelines say there is insufficient evidence that the approach is effective and that it “should not be relied on to preserve fertility.”  Dr. Partridge, who is on the committee that developed the guidelines, said she thought they would have to be reviewed in light of the new study.  The trial, which was sponsored by the National Institutes of Health, involved 257 premenopausal women up to age 49 undergoing chemotherapy before or after having their tumors removed surgically.  Two years after starting chemotherapy, only 8 percent of the women who had received the monthly goserelin injections experienced ovarian failure, compared to 22 percent of those who did not. Twenty-one percent of the women in the goserelin group became pregnant and 15 percent had babies, while in the control group, only 11 percent became pregnant and 7 percent gave birth. Researchers said that difference could not be explained by a difference in the numbers of women who tried to conceive in each group.  In an unexpected finding, the researchers reported that the women receiving goserelin also had a significantly lower risk of dying after four years.  Dr. Jennifer Litton, a breast medical oncologist who was not involved in the study, said that was not enough survival data to recommend that goserelin be used to treat the cancers, but it at least suggested that it would not worsen the cancer outcomes if used to preserve fertility.  Still, Dr. Litton, who is with the M. D. Anderson Cancer Center in Houston, said the trial was fairly small and the chances of a pregnancy were higher with egg retrieval, though the use of one technique would not preclude use of the other. “I don’t think it’s going to be the only thing I’m going to offer for fertility preservation,” she said of goserelin.  Dr. Partridge said there were differences between the new study and many of the previous ones, some of which had shown that the approach was not effective in preserving fertility.  This new trial, she said, measured pregnancy and birthrates, which are better indications of fertility than the loss of menstrual periods, a less direct measure used in many of the previous studies. Some women can lose fertility even if they continue having periods, while others can be fertile even though they do not have periods, she said.  Some of the previous studies also included women with hormone-receptor-positive cancer, meaning tumor growth is fed by estrogen. Women with that type of cancer typically take tamoxifen, which itself can cause loss of menstruation, she said.  The new study included only women with hormone-receptor-negative cancer.  Women with hormone-positive cancer take drugs to suppress estrogen or block its effects and are typically advised not to try to get pregnant for a number of years.  It is not clear why goserelin would protect the ovaries. There is some speculation that making the ovaries less active protects them from chemotherapy. The downside is that goserelin induces a temporary postmenopausal state, which can bring with it hot flashes and other symptoms.  A version of this article appears in print on May 31, 2014, on page B1 of the New York edition with the headline: Drug Saves Fertility for Women With Cancer. Order Reprints|Today's Paper|Subscribe
The new treatment would be a less invasive way to safeguard a woman’s chances of having babies than the current method.