“Cryoresearch Could Give Cancer Survivors a Shot at Motherhood”
by Katherine Kornei
Discover, September 2016
Abby Bott has one of her ovaries in the freezer, and she intends to use it in the future. When stage III rectal cancer struck Bott at the age of 23, doctors told her she’d lose her fertility as a result of the chemotherapy necessary to save her life. Bott opted to have one of her ovaries removed and cryopreserved (i.e., frozen), literally banking on the hope that biomedical research would allow her to have her own biological children in the future.
Women faced with a cancer diagnosis have several options to try and preserve their fertility. They can cryopreserve their fertilized embryos prior to undergoing chemotherapy; these embryos can then be implanted back into the biological mother or a surrogate. This procedure – in vitro fertilization – is now routine in the general population with over 2 million live births from frozen embryos. However, banking fertilized embryos is only an option for women who have partners or women who are willing to use donor sperm. Females of reproductive age also have the option of cryopreserving mature eggs, but the process of retrieving eggs is both surgically invasive and time consuming and may not be possible for individuals who need immediate chemotherapy. A third option for prepubertal or single females diagnosed with cancer is to immediately bank their ovarian tissue, which is the choice Abby Bott made.
The goal of cryopreserving ovarian tissue is to provide women who beat cancer with the option of having their own biological children, if and when they decide to do so. However, the science and ethics of freezing, thawing, and eventually using such tissue are still being explored. To date, only two successful human births have occurred from ovarian tissue that was frozen quickly to inhibit the formation of ice (“vitrified”). Research in the new field of oncofertility is ongoing in primates to determine how viable eggs can be reliably matured in ovarian tissue that was frozen months or even years ago.
Mary Zelinski is an oncofertility researcher at the Oregon National Primate Research Center, a sprawling research campus near Portland that is home to over 5,000 rhesus macaque and Japanese macaque monkeys. Zelinski and her team are working to show that primate ovarian tissue can be successfully extracted, vitrified, thawed, and matured to produce viable eggs. The eggs can then be fertilized and reimplanted back into the monkey, with the end goal of obtaining a live primate birth. Zelinski’s group has achieved a live birth using non-frozen ovarian tissue, which is a first step to replicating the process using cryopreserved tissue.
I envision this feature following two main narratives – a young woman such as Abby Bott who is faced with making decisions about her fertility in light of a cancer diagnosis and an oncofertility researcher such as Zelinski. I see this piece as focusing not only on the science of ovarian tissue preservation but also the complex personal and ethical choices of the process. I’ve exchanged several emails with Zelinski, and I have toured the Oregon National Primate Research Center (30 minutes from my house). I’d reach out to interview Abby Bott if this feature is placed.
Sidebars to this feature could include:
A history of assisted human reproduction starting with the birth of the first baby via in vitro fertilization, Louise Brown, in 1978 and continuing through the current trends of pre- implantation genetic diagnosis to select embryos that do not carry specific disease markers.
A visual overview of the steps of extracting, freezing, thawing, and maturing ovarian tissue.
Ethical questions of banking ovarian tissue: Should this procedure be available to any woman wishing to stop her biological clock or just to cancer patients? Who owns the ovarian tissue? Can the tissue be used for research if the patient doesn’t survive her cancer? Why pays for the procedure?
This feature is relevant because 10% of cancers strike women during their reproductive years. Cancer survival rates are also increasing thanks to new therapies so patients and their parents are increasingly able to think of cancer as a disease whose effects must be managed rather than a terminal diagnosis.