Ovarian tissue transplant may help cancer survivors become pregnant
An experimental technique that involves removing, freezing, and later transplanting ovarian tissue appears to be safe and can help about one third of women to have babies. But experts say more research is needed to validate the results.
The procedure is intended for women who've had cancer who wish to preserve their fertility, since cancer treatments such as chemotherapy and radiation can harm the ovaries. It typically involves removing one ovary and cutting it into strips before freezing the tissue. Years later, cancer survivors can undergo a graft of some of the thawed-out tissue onto their remaining ovary.
For the study, researchers followed 41 women from Denmark who underwent the procedure between 2003 and 2014. The women's average age when the tissue was removed and frozen was close to 30. The average age of the first transplant was 33.
Among the 32 women in the study who wanted children, 10 became pregnant and gave birth.
"Once we transplant the ovarian tissue, it takes about four to five months for the ovary to get restarted," said Dr. Claus Yding Andersen of Copenhagen University Hospital, the study's senior author. The paper was published online Wednesday in the journal Human Reproduction.
In some cases, the transplanted tissue lasted up to a decade, much longer than the 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, in South Yorkshire, England. He said mothers and babies required close monitoring although no potential problems linked to the technique have been noted so far.
In the study, three women later experienced 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."
Currently, women preparing for cancer treatment might have eggs or embryos frozen for later use, but for this procedure, Dr. Jane Stewart of the British Fertility Society said the technique won't be suitable for everyone and that doctors need to be careful about selecting which patients to treat.
"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," Stewart said.