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CHICAGO — Doctors may have found a way to help young breast-cancer patients avoid infertility caused by chemotherapy. Giving a drug, goserelin, to shut down the ovaries temporarily seems to boost the odds they will work after treatment ends, and it might improve survival, a study found.

“They’re really exciting findings” that could help thousands of women each year in the United States alone, said the study’s leader, Dr. Halle Moore, of the Cleveland Clinic.

“This has implications far beyond breast cancer” for young women with other types of tumors, too, said Dr. Clifford Hudis, breast-cancer chief at Memorial Sloan Kettering Cancer Center in New York City.

He is president of the American Society of Clinical Oncology, which featured the study at its annual conference in Chicago on Friday. More than 30,000 cancer specialists from around the world are attending.

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“It’s not a panacea, but based on these data, it may be the right choice for some patients,” said Dr. Ann Partridge, a breast-cancer specialist at the Dana-Farber Cancer Institute in Boston and another author of the study. She said about 16,000 U.S. women younger than 45 get breast cancer each year.

Goserelin and similar drugs 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. Goserelin is sold by AstraZeneca under the brand name Zoladex. Global sales of the drug were about $1 billion in 2013.

Chemotherapy often causes premature ovarian failure, or early menopause. Doctors think that active ovaries are more susceptible to damage from chemotherapy, and that making them go dormant and stopping a woman’s monthly cycles might help shield them from harm.

“It’s basically a temporary menopause to prevent permanent menopause,” Moore explained.

The study involved 257 women around the world younger than 50 with breast tumors whose growth was not fueled by estrogen. They all had standard chemo and half also had monthly shots of goserelin, a drug to lower estrogen and temporarily put the ovaries at rest. Its main side effects are menopause symptoms — hot flashes and vaginal dryness.

Doctors then tracked the women to see how the treatments affected fertility.

After two years, full results were available on 135 participants. Only 8 percent of those given the shots became menopausal versus 22 percent of the others who didn’t get them. There were 22 pregnancies in the drug group versus 12 in the other one.

That’s encouraging, but firm comparisons can’t really be made because not all women may have been trying to conceive, and other factors such as a partner’s fertility play a role.

Still, “the difference was enough that in spite of all the limitations in the study, we were pretty convincingly able to see an effect,” Moore said.

The benefits go beyond preserving fertility, said Dr. Kathy Albain, a breast-cancer specialist at Chicago’s Loyola University and one of the study leaders.

“Some women don’t care about having children” after breast cancer but would like to avoid “being jolted into early menopause” by chemo treatment, she said.

Surprisingly, doctors also saw better survival among women given goserelin. About four years after treatment, 92 percent of them were alive versus 82 percent of the others. Again, an encouraging result, but the study was too small to determine whether ovarian suppression affects survival.

The National Institutes of Health sponsored the study and researchers originally aimed to enroll 400 women but had to scale back because of government budget cuts.

“The findings are quite provocative,” said one independent expert, Dr. Sharon Giordano, a breast-cancer specialist at the University of Texas MD Anderson Cancer Center in Houston. “Using goserelin is an option I would discuss with selected patients” but it doesn’t guarantee fertility preservation.

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 costing thousands of dollars, 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.

The goserelin approach worked for study participant Christy Wolford, who was treated at MD Anderson before she moved to Fort Collins, Colo., a few years ago. She was 28 when her breast cancer was found, and she wanted more children besides the 5-month-old daughter she had at the time. Her ovaries were suppressed during cancer treatment and she has had three boys since treatment ended in 2006.

“I’m the poster child” for the study, she said.

Material from The New York Times is included in this report.

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