Two-year-old girl benefits from technique to save cancer patients' fertility

A two-year-old girl has become the youngest patient to benefit from a new technique to preserve the fertility of young cancer patients.

The therapy - carried out in the UK - could pave the way for very young cancer patients to put their "fertility on ice" while they undergo gruelling treatments, which can leave them infertile.

Experts have been perfecting techniques to preserve fertility in all age groups, and around 50 babies have been born worldwide following successful ovarian tissue freezing.

But there are currently very few options for younger girls who have not yet gone through puberty.

In the new research, experts at Oxford Fertility and Oxford University successfully managed to extract immature eggs from young girls, grow them in the lab until they were mature, and then quickly freeze them for a future date.

They also froze ovarian tissue with a view to potentially transplanting it back into the girls in the future, in the hope their bodies start producing their own eggs.

The two-pronged approach, which builds on expertise already established in Oxford, could enable young girls to bear their own children when they are older.

Professor Tim Child, from the University of Oxford and medical director of Oxford Fertility, said the technique offers patients and scientists "two bites of the cherry".

In the study, 15 young girls aged two to 17, and eight women aged 22 to 31, took part in the research between 2013 and 2015.

Ovarian tissue and immature eggs were removed, and the eggs matured in the lab using an established technique known as in vitro maturation (IVM).

The resulting mature eggs and the tissue were then frozen by scientists.

Experts were able to extract immature eggs in 80% of the children and 75% of the women in the group, and managed to freeze 60% of the girls' mature eggs and 40% of those in the women.

IVM has the advantage of avoiding the risk that potentially cancerous cells are reintroduced to a woman at a later date.

Prof Child said: "If we're looking at fertility preservation in adolescent or pre-pubertal girls, then, around the world in general, not a lot can be done for them.

"In Oxford, we have taken a belt-and-braces approach.

"During the procedure - which is a laparoscopy - some ovarian tissue is removed and some of the cortex of the ovary is removed. At that point, other fertility centres would just freeze the tissue. But what we do is look at the tissue down the microscope and we look for the immature follicles that contain immature eggs.

"This is the same as we would do with normal IVM.

"We then use a needle to aspirate the immature eggs out, mature the eggs for 24 to 48 hours and then once mature, we freeze those eggs. They are fully formed at this point."

Prof Child said it was not yet known whether the technique would be more successful than tissue freezing alone, but the team "have good reason" to think it would work.

"It's two bites of the cherry - we freeze the tissue and freeze the matured eggs," he said.

He said the two-year-old girl, who cannot be named, was "definitely the youngest" to have eggs frozen using IVM.

He added that the "holy grail of fertility preservation" is being able to grow and freeze lots of eggs, and research was currently ongoing that suggests researchers will be able to grow "almost countless eggs from frozen ovarian tissue" in the future.

He said: "But, at the moment, all we can say is there have been births from ovarian tissue transplanted back into woman. We've also had births from IVM so there's no reason not to think we would have success from this new technique."

The findings were presented at the European Society of Human Reproduction and Embryology (Eshre) conference in Helsinki.