LONDON (AP) — The biggest
study ever of women who had ovarian tissue removed, frozen and transplanted
suggests the experimental technique is safe and can help about one third of
them to have babies.
The procedure is intended for women with
cancer who wish to preserve their fertility, since cancer treatments can harm
the ovaries. Scientists typically remove one ovary and cut it into strips
before freezing them. Years later after the woman has recovered from cancer,
doctors typically graft some of the thawed-out tissue onto the remaining ovary.
Researchers followed 41 women in Denmark
who underwent the procedure from 2003 to 2014. Among the 32 women in the study
who wanted children, 10 later got pregnant and gave birth. Globally, more than
36 babies have been born to women who had ovary transplants, with 14 in
Denmark.
Unlike most countries, Denmark offers the
treatment free to all women who qualify. The technique is not part of routine
cancer care in Britain, but is available at some clinics there and in Europe,
including Belgium and Germany.
"Once we transplant the ovarian
tissue, it takes about four to five months for the ovary to get
restarted," said Dr. Claus Yding Andersen, the study's senior author. The
paper was published online Wednesday in the journal, Human Reproduction.
In some cases, the transplanted tissue
lasted for up to 10 years, much longer than scientists had predicted.
The ovarian tissue that kept
working so long probably had more eggs to begin with, said Mark Fenwick, a
lecturer in reproductive and developmental medicine at Sheffield University. He
said mothers and babies required close monitoring although no potential problems
linked to the technique have been spotted so far.
In the study, three women later had a
cancer relapse, but Andersen said that didn't appear to be linked to the
transplant.
"This technique still needs to be
further validated, but the results are reassuring," said Dr. Yacoub
Khalaf, director of the Assisted Conception Unit at Guy's Hospital in London,
who is also working to refine the procedure. "It offers hope to people who
have no other alternative."
Dr. Jane Stewart of the British Fertility
Society said the technique wouldn't be suitable for everyone and that doctors
need to be careful about selecting which patients to treat. At the moment,
women preparing for cancer treatment might have eggs or embryos frozen for
later use.
"I think patients would definitely
want (the option of transplanted ovarian tissue) and there is a lot of future
potential, but this isn't ready to be rolled out tomorrow," she said.
