Freezing Eggs of Cancer Patients.

• Position: Brief Article

Female cancer patients and other women at risk of losing their fertility because of medical treatments can help preserve their childbearing options through a new egg-freezing program at Stanford (Calif.) University Medical Center. Under it, women ages 18 to 40 who are undergoing chemotherapy, radiation, or surgical removal of the ovaries can choose to have their eggs retrieved before treatment and then stored indefinitely in a freezer for possible future fertilization.

"A lot of people don't realize that there are things we can do that may help future fertility," indicates Lynn Westphal, assistant professor of gynecology and obstetrics and director of the medical center's donor oocyte program. "It's something women should know about and have a discussion about before they have chemotherapy or other treatment for their disease. Later on, we may not be able to reverse the damage to the ovaries."

Unlike eggs, sperm have long been frozen and utilized for preservation of future fertility, in part because the use of sperm presented less of a technical challenge. As sperm are much smaller than eggs, they survive the freezing and thawing process relatively unscathed. However, the use of frozen eggs in IVF treatment became a viable option in the mid 1990s with the introduction of a technique called intracytoplasmic sperm injection, which involves injection of a single sperm into a single egg in order to achieve fertilization. Using ICSI, the chance of success is much higher, with reported fertilization rates approaching 65%.

"I think we only figured out recently that frozen eggs don't fertilize well with normal fertilization," indicates Barry Behr, assistant professor of gynecology and obstetrics and director of Stanford's In Vitro Fertilization (IVF) and Assisted Reproductive Technologies laboratories. "But they fertilize reasonably well with ICSI." That is because the freezing process damages the zona pellucida, the outer shell of the egg, to which...