Drug shown to shield cancer patients' fertility

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 Friday.

The treatment could provide a new option for dealing with one dilemma 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 fertility. 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.

"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 an author of the study, which is being presented at the annual meeting of the American Society of Clinical Oncology.

Partridge said about 16,000 U.S. women younger than 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 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.

Injections of goserelin could be a less expensive and easier alternative. But until now, studies testing it 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."

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 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 with 22 percent of those who did not. Twenty-one percent of the women in the goserelin group became pregnant, compared with 11 percent in the control group, and they gave birth to more babies.

Researchers said the 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 data to recommend that goserelin be used to treat the cancer, but it at least suggested that it would not worsen the cancer outcomes if used to preserve fertility.

Litton, who is with the M.D. Anderson Cancer Center in Houston, said the trial was still fairly small and that the chances of a pregnancy were still 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.

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 rates, which are a better indication 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 can cause loss of menstruation, she said.

The new study included only women with hormone-receptor-negative cancer. Partridge said she thought the findings could be extrapolated to those with hormone-receptor-positive cancer as well. However, women with hormone-positive cancer take drugs to suppress estrogen and are typically advised not to try to get pregnant.

A Section on 05/31/2014

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