Frozen eggs give hope of future motherhood to cancer children

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A PIONEERING operation for young girls suffering from cancer may enable them to have powerful radiation treatment without damaging their chances of having children years in the future.

Thousands of girls, some as young as three, will have their eggs removed and stored before they undergo potentially fertility-damaging therapy.

In the past, this process of ovarian tissue-freezing has been used only for research purposes but it will now be available at three hospitals - Glasgow Royal Infirmary, Leeds General Infirmary and Edinburgh Royal Infirmary.

The process involves the preservation of a small portion of ovarian tissue, containing hundreds of unfertilised eggs, from the womb.

The pea-sized piece of tissue is then kept frozen in liquid nitrogen at a temperature of minus 200C. The remaining part of the ovary is then pushed further down the body to keep it as far away from the cancer treatment as possible.

Years later, if the patient survives and decides to have a family, the tissue is thawed and cultured in a laboratory in the hope it will provide mature eggs to be fertilised and then transferred back as embryos. There is expected to be an increasing demand for this service as the number of children surviving cancer increases. There are now more than 10,000 adults who have survived childhood cancer - twice the figure of 25 years ago.

At present, doctors are still developing the technique to culture the frozen-thawed ovarian tissue to produce viable eggs. But scientists at Glasgow and Leeds universities are confident that the technology will be generally available in the next few years.

There is some opposition to the technique from some doctors, based on the fear that cancer cells could survive in the frozen eggs and cause a recurrence of disease when reimplanted.

Others have questioned the viability of preserving the ovary in suspended animation. They have suggested it could degenerate during the 15 or more years in which it is stored.

But scientists involved in the project are confident about its benefits. They say there are more than 600 new cases a year of young girls developing cancer and these could all be offered hope through ovarian tissue freezing.

"A woman is born with a fixed amount of eggs which deteriorate as she gets older," said Dr Non Thomas, a research embryologist at Glasgow Royal Infirmary who has been involved in the project to freeze ovarian tissue.

"Young girls are therefore suited to the treatment because they have a large amount of eggs. The criterion is that in 10 or 15 years' time they will be able to use the tissue to become mothers. That their fertility will not be impaired is a weight off their minds, and those of their parents."

In 1995, a three-year-old girl made medical history when she became the first child to have her ovary tissue frozen.

Doctors removed a small piece of tissue from one of the ovaries of Harriet Selka before giving her radiation treatment for a kidney tumour.

Harriet, who now lives in Lincoln, was treated by doctors at Leeds when she was struck down by Wilm's Tumour at the age of 18 months. Now aged six, she still has to have regular check-ups to ensure she is free of the cancer but otherwise she is able to enjoy a normal childhood.

Her parents, Elizabeth and William, say they were fortunate that their daughter had the opportunity to benefit. "It was a radical treatment at the time," said Mr Selka. "Harriet's condition worsened so she had to have more intensive treatment. We were lucky that we were offered this treatment and given a chance for Harriet to have children."