Ovarian tissue autotransplantation

A 28-year-old Israeli woman, who was cured of non-Hodgkin’s lymphoma, gave birth to a healthy baby in June 2005 after her own banked ovarian tissue was re-implanted.[1]

The woman’s tissue was removed and preserved in a freezer before she received high-dose chemotherapy, a treatment that is known to cause ovarian failure. Two years after her complete recovery, the tissue was re-implanted, and this resulted in the production and retrieval of a mature egg. After the egg was fertilized in vitro with her husband’s sperm, the resulting embryo was transferred to her uterus, where the fetus developed normally.

A mature egg may develop from transplanted ovarian tissue.

Photo courtesy of Dr. RC Chian, McGill Reproductive Centre.

This appears to be the third reported case of a woman giving birth after receiving transplanted ovarian tissue.

In June 2005, an infertile woman received an ovarian tissue transplant from her identical twin sister and gave birth to a baby after normal conception.[2]

Last year, a team of Belgian physicians announced that a 32-year-old woman who was cured of Hodgkin’s disease had given birth to a baby after her ovarian tissue, which was frozen for six years, was successfully re-implanted.[3]

Cryopreservation of ovarian tissue is one of several options for women who may become infertile after aggressive cancer treatments.

Ovarian tissue is removed by laparoscopy, a surgical procedure in which a scope is inserted through a small incision in the abdomen. The tissue is then preserved in liquid nitrogen and frozen. When the tissue is carefully thawed and re-implanted, fertility drugs may be used to induce ovulation.

Canadian access to the technology

While the procedure is still in its infancy, the McGill Reproductive Centre in Montreal began offering ovarian tissue cryopreservation four years ago.

Dr. Togus Tulandi, a professor of obstetrics and gynecology, and a fertility expert at the McGill centre, said that he has collected ovarian tissue samples from 20 to 30 women. Some women have travelled to the Montreal clinic from Ontario and Nova Scotia.

“So far, we have not transferred any tissue back to the patients,” Dr. Tulandi said. Women must first undergo cancer treatment, then wait for a full remission and recovery before making the decision to conceive a child. None of the McGill centre’s patients have reached this stage yet.

Ovarian tissue banking is not yet offered at any other Canadian sites.

Risks of tissue re-implantation

Candidates for ovarian tissue autotransplantation must be selected carefully because there is a risk that some malignancies, such as lymphoma or leukemia, might be re-introduced through the grafted tissue. More reliable and sensitive screening technologies are needed to detect residual cancer cells.

Other fertility options

Other ways of preserving fertility include ovarian suspension to move the ovaries out of the range of the intended pelvic radiation; cryopreservation of immature and mature oocytes for future in vitro fertilization; or embryo preservation.

The harvesting of mature oocytes requires that women take fertility drugs for several weeks before collection. This could delay urgent cancer treatment. There is also concern that this could aggravate hormone-sensitive cancers.

By contrast, ovarian tissue can be retrieved at any stage of the menstrual cycle without compromising a woman’s health or fertility, allowing chemotherapy treatment to be started without delay.

Still considered to be experimental, the ovarian tissue transplantation procedure requires refinement to improve tissue harvesting, the freeze-thaw process and the grafting technique.

References

[1] Meirow D et al. N Engl J Med 2005;353(3):318-21.

[2] Silber SJ et al. N Engl J Med 2005;353(1):58-63.

[3] Donnez J et al. Lancet 2004;364(9443):1405-10.