Cryopreservation boosts fertility hopes to breast cancer patients

Cryopreservation boosts fertility hopes to breast cancer patients

23 Jun 2015

Breast cancer patients can achieve pregnancy rates comparable to those for women in the general population undergoing in vitro fertilization (IVF), thanks to embryo cryopreservation after ovarian stimulation with letrozole and follicle-stimulating hormone, according to a new study.

Investigators led by Kutluk Oktay, MD, a professor of obstetrics and gynecology at the Innovation Institute for Fertility Preservation and In Vitro Fertilization in New York City, reported on fertility preservation in 131 women no older than 45 years with stage<3 breast cancer who underwent ovarian stimulation with cryopreservation of IVF-generated embryos before receiving adjuvant chemotherapy. Estrogen-receptor-positive tumors were present in 69% of patients, 18% carried a mutated BRCA gene, and 57% had received tamoxifen.

“Women transfer embryos to their own uteruses or to a gestational carrier”

In all, the women underwent 152 cycles of embryo cryopreservation at a mean age of 35.8. Of the 131 patients, 17 had two cycles of embryo cryopreservation and two women had three cycles, resulting in a mean number of 5.9 cryopreserved embryos.

At the time of analysis,

• 33 women had returned to the institute and in all underwent 40 attempts to transfer embryos to their own uteruses or to a gestational carrier at a mean age of 41.5 and a median interval of 5.25 years after embryo cryopreservation.

"The reasons for using a gestational carrier were that these women were either undergoing treatment with tamoxifen which precluded gestation or they were concerned about the safety of pregnancy after breast cancer although no prior studies have suggested an increased risk of relapse," wrote Oktay and colleagues.

Patients got prepared using an artificial programmed menstrual cycle

The institute developed its combination protocol to protect breast cancer patients from traditional ovarian stimulation, which can result in estrogen levels 10 to 20 times higher than physiologic concentrations and raises concern about accelerated tumor growth in patients with estrogen-sensitive tumors.

Patients and gestational carriers were prepared for embryo transfer with an artificial programmed menstrual cycle.

The mean number of embryos transferred was 1.97. The overall clinical pregnancy rate was 65.0%, the implantation rate was 40.7% and the live birth rate (25 babies) was 45.0%.

No fetal anomalies or malformations were reported

No fetal anomalies or malformations occurred, and parents reported no developmental problems at last follow-up. Furthermore, no medical complications during pregnancy or in the postpartum period were reported.

"Our findings contribute to the safety track record of the letrozole protocol and indicate that letrozole has no detrimental effect on the oocyte, the resulting embryos, or the offspring," Oktay and his associates wrote. "Given this sustained track record, we surmise that the letrozole protocol should be used more commonly to offer the possibility of [fertility preservation] by established cryopreservation methods in women with breast cancer."

Easier for patients to delay pregnancy to complete adjuvant therapy

Commenting in an accompanying editorial, Pamela N. Munster, MD, a breast oncologist at the Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, pointed out that the study -- though small and in a single-center with no explanations for the low return rate -- suggests another option for breast cancer patients to have a biological child.

These findings should make it easier for patients to delay pregnancy to complete adjuvant therapy. However, further insights into reasons for the low return rate and the outcomes of the non-returning patients with regard to spontaneous pregnancies would be helpful to better leverage this promising strategy and make it more feasible for a larger proportion of women in need.

Source: MedPage Today