Preserving fertility in pre-pubesent female cancer patients
A pioneering new medical procedure in the UK has allowed the oocytes (immature eggs) of a two year old girl to be frozen. This patient was one of fifteen children aged between two and fifteen that participated in the research. All fifteen young patients suffer from cancer.
This treatment aims to preserve their genetic fingerprint in the event that subsequent radiation and chemotherapy treatments lead to infertility. Specialists involved in this procedure at the Oxford Fertility Clinic in Britain hope that this will provide the young girls with a chance to still be mothers later in life.
Prior to the patients undergoing treatment for cancer the doctors performed an in-vitro maturation (IVM) procedure. The patients oocytes where harvested and then incubated to maturity in the laboratory prior to freezing. The eggs can stay frozen for 20 to 30 years and still retain viability. Ovarian tissue from the patient was also frozen. However, there is no guarantee of a successful pregnancy when the patients want to start a family.
IVM versus IVF
The main difference between IVM and conventional in vitro fertilisation (IVF) is that the eggs are immature. They are collected and matured outside of the body in a laboratory setting. The advantage of IVM over IVF is that the patient does not have to take medications such as follicle stimulating hormones and luteinizing hormones prior to egg harvesting.
IVM is usually only preformed when patients are susceptible to developing OHSS (ovarian hyper-stimulation syndrome) or have PCOS (polycystic ovarian syndrome). OHSS is a potentially dangerous condition where a patient can have an adverse reaction to fertility drugs. Some fertility clinics prefer to use IVM treatments as opposed to IVF when the patient suffers from PCOS as this can improve conception rate[1. “Child, T. et. al (2002). A comparison of in vitro maturation and in vitro fertilization for women with polycystic ovaries. Obstetrics & Gynecology. Volume 100, Issue 4, (pp. 665-670).”].
Generally, the chances of conceiving through IVM are similar to IVF. However, there are additional risks. Fewer eggs are harvested during IVM compared with a conventional IFV cycle. Also, there is a high probability that not all the eggs with successfully mature. Despite these risks, many babies have been born thanks to IVM.
IVM and young patients.
How effective the IVM technique is when applied to patients as young as two remains to be determined. To facilitate this procedure a laparoscopy was preformed to remove part of the ovary.
The tissue was then examined under a microscope to locate the most developed of the immature eggs. These eggs where then placed into a culture with growth factors and hormones and incubated overnight to stimulate maturation prior to freezing. Approximately 60% of the removed ooctyes reached maturity and were able to be put on ice.
Preserving ovarian tissue
As part of this research, doctors also removed and preserved patient’s ovarian tissue. The idea behind this is that the tissue can later be introduced back into their bodies and start to produce eggs again. Approximately 50 babies have been successfully born from re-introducing ovarian issue.
Giving cancer patients new hope
Although there have been many advances in cancer treatments, the fact remains that radiation and chemotherapy are toxic to the body. The fallopian tubes, ovaries, uterus, and cervix can become irreversibly damages. Further to this, many survivors also have a much shorter reproductive window due to increased probability of early menopause.
Taking advantage of fertility preservation options may help female cancer survivors to become mothers when they are ready to start a family. How successful these treatments will be for patients that haven’t even reach puberty remains to be determined. However, with new development in fertility research and advances in technology, even very young cancer survivors may still be able to have a family of their own in the future.
The findings of the study discussed were presented at the European Society of Human Reproduction and Embryology annual conference held in Helsinki.
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