TUESDAY, April 12, 2005 (HealthDay News) -- Combining a cancer drug with a fertility hormone used for in vitro fertilization (IVF) may preserve the fertility of breast cancer patients before they undergo chemotherapy without promoting the growth of breast cancer, a new study finds.
About 15 percent of women diagnosed each year with breast cancer in the United States -- about 25,000 patients -- are still of childbearing age, and they quickly learn that most chemotherapy regimens adversely affect ovarian function.
But the new approach may make it more feasible for these women to undergo IVF before treatment and freeze their embryos. Once treatment is finished, those eggs can then be implanted, if needed.
The new combination therapy "appears to be safe," said study author Dr. Kutluk Oktay, director of the fertility preservation program at The Center for Reproductive Medicine and Infertility at New York Presbyterian Hospital/Weill Cornell Medical Center, in New York City.
"With the limited follow-up, we did not see any increased incidence of cancer recurrence," he said. The follow-up averaged about a year and a half.
However, in an accompanying editorial, two authors from Dana-Farber Cancer Institute caution that the numbers are too small and the technique too preliminary to say with assurance that it is safe.
The report appears in the April 11 issue of the Journal of Clinical Oncology.
Oktay and his team studied 60 young women diagnosed with breast cancer. Twenty-nine underwent IVF and 31 chose not to undergo the fertility procedure.
Standard fertility drugs used during IVF increase estrogen levels and may promote the growth of breast cancer cells. So, Oktay's team added one of two cancer drugs to the regimen. These drugs, tamoxifen and letrozole, stimulate ovulation without promoting the growth of breast cancer cells.
The women who underwent IVF were divided into three groups: One received tamoxifen alone; another tamoxifen in combination with low-dose follicle-stimulating hormone (FSH), which stimulates egg production; while the third group received letrozole (Femara) along with low-dose FSH.
"We found that letrozole with FSH produced more eggs and on average one extra embryo, compared to tamoxifen and FSH, and four times more than tamoxifen alone," Oktay said. The average number of embryos was just over five in the letrozole and FSH group, close to four in the tamoxifen-plus-FSH group, and 1.3 in the tamoxifen-alone group.
One patient returned and had an embryo transferred to a surrogate, but the pregnancy miscarried in the first trimester, Oktay said. Since the paper's publication, another woman returned for embryo transfer and is pregnant, he added.
The 27 other patients who underwent IVF have not yet returned for embryo transfer, Oktay said.
The cancer recurrence rate was similar between the IVF group and the control patients, he found. Three of the 29 who underwent IVF and three of the 31 who did not get IVF reporting a recurrence of their breast cancer during an average follow-up of 18 months.
Dr. Ann H. Partridge, a medical oncologist and clinical researcher at Dana-Farber Cancer Institute, co-authored an editorial with Dr. Eric P. Winer, also of Dana-Farber. While she applauded Oktay's attempts to preserve fertility in breast cancer patients, she also had some caveats.
Because the numbers are small and the follow-up brief, Partridge said, "I think it is way too early to say anything remotely definitive about the safety of this procedure."
In the editorial, Winer and Partridge also wrote: "Given the low pregnancy rates reported in the study by Oktay et al, the true benefit of these strategies has yet to be determined."
To learn more about infertility, visit the American Society for Reproductive Medicine.