Fertility Preservation
For Cancer Patients by Use of IVM and IVF: An Update
This update is provided by New York Fertility Services in New York City. A resource for information in the area of fertility preservation is www.fertilehope.org
Treatment for cancer in woman under the age of 40 is successful in 80% of cases. Often in leukemia and other diseases the women are quite young and have not had a family. The surgery or chemotherapy sometimes threatens the eggs and future fertility. Before treatment women with a male partner may have IVF and embryo cryopreservation. Women with no partner may have ovarian stimulation and egg retrieval with freezing of the eggs. However, this requires 4-7 weeks of planning and treatment. The cancer treatment is usually under considerable time pressure, and naturally has to be the priority.
Ovarian tissue cryopreservation is still an experimental development with unknown potential. An attractive alternative for some women will be cryopreservation of eggs. Recent advances in quick freeze method called vitrification have dramatically improved the success of egg survival after thawing. In order to hasten the process and lower the cost of acquiring the eggs, the pioneering group at McGill University in Montreal has used in vitro maturation (IVM) to harvest eggs. In this method, no gonadotropin is used and the eggs are obtained deliberately from medium size follicles. The eggs are matured in vitro, then frozen. Years later when sperm are available, IVF can be done.
The McGill group recently reported its use of this approach with a birth resulting. The protocol involves only a week or two at most. In this case young (age 27) infertility patient was treated as a proof of principle. Nineteen eggs were retrieved, 16 matured, 17 were frozen, 4 survived the thaw and the three embryos replaced led to a singleton pregnancy. Though not tested in a cancer patient, certainly this was a successful demonstration that the method could apply when appropriate.
This is a new use of IVM which now has been applied systematically in humans for over 10 years. Pregnancy results range from 35% to 48% with live birth rates about 20% lower after miscarriages which may occur at slightly higher than usual rates. Newborn outcomes to date confirm normal development. These can be compared to average rates in IVF centers across the US. The pregnancy rates from egg freezing would be expected to be lower. However it is likely to be used as an option for fertility preservation in the near future. IVM is used regularly in Canada, Korea, China, Scandinavia and France.
Yet to be explored is the possibility of multiple retrievals in one cycle. This is based on the observation by Baerwald that there are 2-3 waves of follicles emerging in a given month.
