Through recent advances in oncology, cancer survival rates are increasing. As you are aware, many cancer treatments cause loss of reproductive function. As these survival rates increase and women are able to think about life after cancer, fertility preservation is becoming increasingly more important.
Options for fertility preservation vary depending on a woman’s marital status or willingness to use donor sperm. The gold standard for fertility preservation is Embryo Cryopreservation. This is an ideal option for a married woman or a woman willing to use partner or donor sperm. Chance of achieving pregnancy using frozen embryos is 40-50% per attempt. This high success rate is unparalleled and this should be offered as first line therapy for women who have a partner.
Creation of embryos for fertility preservation requires in-vitro Fertilization. “Emergency IVF” protocols have been developed for fertility preservation in order to rapidly stimulate the ovaries and take the patient through the process in 2 weeks. Many patients often have a window of time between surgery and chemotherapy where they would be able to undergo IVF. For others, a 2-week delay may still be acceptable. In order to create embryos, the patient must undergo a series of daily injections to stimulate the ovaries to produce multiple follicles. Each Follicle contains a singleOocyte. For women who have estrogen responsive tumors, adjuvant treatment with tamoxifen or letrozole duringStimulation prevents the estrogen levels from rising too high. Response to stimulation is monitored with daily ultrasounds and blood tests. When the follicles have shown appropriate growth, the patient undergoes transvaginal oocyte retrieval under anesthesia. The oocytes are then inseminated with sperm from a partner/donor. Oocytes that have fertilized cleave to become embryos and the embryos are vitrified and stored for future use.
Vitrification is a rapid cooling technique that prevents ice crystal formation and causes less damage to the cells. Embryos can be stored without detriment for 5 years and pregnancies have been reported in embryos stored for 10 years.
For women without a partner or who are uncomfortable with the idea of using donor sperm, protocols are being developed to retrieve the oocytes and vitrify the oocytes without insemination. Once the woman has completed her cancer treatment and is ready to start a family, the oocytes would be warmed and inseminated with sperm. Embryo development would then ensue and those embryos would then be placed into her uterine cavity.
Vitrification protocols are starting to enter the mainstream of human assisted reproductive technology and have been used successfully since 1999. At Fertility Centers of Illinois, we have been successfully using vitrification protocols for embryo cryopreservation since 2004. In our program, we have a 92% survival rate for blastocysts after warming. These vitrification protocols have been modified in order to freeze oocytes. In a paper published by Lucena et al., in Fertility and Sterility 2006 the investigators reported outcomes on vitrified oocytes from 23 women. They noted an 80% oocyte survival rate after warming, 90% fertilization rate and a subsequent pregnancy rate of 56.5%. Clearly the feasibility of vitrification of human oocytes has been confirmed. It is important to note, however, that because the numbers are still very small, the American Society for Reproductive Medicine (ASRM) considers egg freezing investigational. For women facing cancer and potential loss of reproductive function, this is a viable option.
If you feel that your patients may be candidates for oocyte cryopreservation, our physicians and clinical psychologist are available to help counsel your patients regarding this important aspect of their fertility preservation. Please contact us at 877-FCI-4IVF or www.fcionline.com.