WEDNESDAY, Jan. 8, 2003 (HealthDayNews) -- Tamoxifen, used widely to prevent reoccurrences of breast cancer, seems to have another benefit for women with this disease -- increasing their chances for fertility.
For premenopausal women diagnosed with breast cancer, taking tamoxifen nearly tripled their ability to produce embryos that could be stored for later in vitro fertilization (IVF) before they began chemotherapy, says Dr. Kutluk Oktay, a reproductive endocrinologist in New York City.
"Tamoxifen brings about completely opposite responses in different parts of the body -- it is sort of a right fit for everybody," says Oktay, lead author of a study on the effects of tamoxifen on embryo production among breast cancer patients.
While the drug blocks estrogen receptors in the breast, key to reducing the incidence of recurrent breast cancers, it acts in just the opposite way on the endometrium, stimulating follicle growth in the ovaries and increasing the chances of producing embryos.
The results of the study appear in the January issue of Human Reproduction.
The chemotherapy used to treat breast cancer causes ovarian failure in as many of four out of five women. It also brings on earlier menopause, Oktay says, which is devastating for younger women facing breast cancer.
"For many women it is more upsetting to find out they can't have a child than it is to learn they have cancer," he says.
However, he says that taking tamoxifen for at least one menstrual cycle before starting chemotherapy treatments -- which begin about six weeks after surgery -- lets the women produce embryos that can be fertilized and stored for later IVF.
In the study of a dozen women, aged 23 to 42, who were diagnosed with breast cancer, the women took 40 milligrams to 60 milligrams of tamoxifen daily beginning on day two or three of their menstrual cycle and continued the drug for an average of seven days while Oktay and his colleagues monitored them. A control group of five breast cancer patients who received no tamoxifen was also monitored. Several of the women in both groups repeated the study for a second menstrual cycle.
Oktay found the women who took tamoxifen during their menstrual cycles before chemotherapy all produced one or more embryos that could be saved for IVF. Of the control group of five women who took no tamoxifen, only three produced an embryo and each one produced only one embryo each.
"On average, the women on tamoxifen produced two embryos instead of one or none among the unstimulated group, so statistically, the women on tamoxifen were about three times more likely than those women not stimulated to have produced embryos," he says.
"The strategic idea of women with breast cancer saving embryos is OK and stands on its own, but this is not a massive study and there are not enough numbers to talk about," says Dr. John Larsen, a George Washington University Hospital gynecologist and obstetrician.
Oktay acknowledges the study is small, and long-term data on resulting pregnancies is not yet available. However, he says the findings are strong enough that women of reproductive age should know about this option if they are diagnosed with breast cancer. About 15 percent of women with breast cancer, about 27,000 women annually, fall into this category.
"The issue is to get this news out to patients. The number one complaint I hear from patients is that they didn't know their treatment would affect their fertility," he says.
Often doctors, predictably more concerned about treating a life-threatening illness than fertility, neglect to talk to their patients about it, Oktay says, so women are unaware of the effects of the chemotherapy.
"Women have to ask their physicians about it," he says. "Often this is the only bright spot for them. It's a matter of having control over their bodies."
What To Do
Information about tamoxifen can be found at the American Cancer Society. For a fact sheet about infertility, visit the Mayo Clinic.
