Fertility Preservation for Cancer Patients

Freezing of eggs or ovarian tissue to preserve fertility for cancer patients has been studied since 1994 with Gosden’s original paper in sheep, and before that in smaller mammals for decades prior. Clinically, this tactic has enjoyed great success. Despite the rising popularity of vitrification for egg freezing, it is often done incorrectly, forgetting the original principles Kuwayama established in 2005. So there will be many disappointed patients around the world whose egg freezing was not done well. Greater care to very gradual osmotic shifts and “open” super rapid freeze and thaw will be required to make egg freezing with vitrification more reliable. Many healthy children have been born from the Kuwayama egg vitrification technique for social indications, but until now very few cancer patients have yet to get pregnant from frozen eggs for several reasons. Often, oncologists do not wish to delay cancer treatment while the patient goes through multiple stimulation cycles to retrieve eggs, and the patient can only start using the oocytes after full recovery. Furthermore, egg vitrification is much more sensitive to error than ovary tissue freezing. However, over 40 healthy babies so far have been born from ovary tissue freezing for cancer patients and have had complete return of hormonal function, as well as fertility. Therefore both egg freezing and ovarian tissue freezing seem now to be ready to be applied to preserving fertility for cancer as well as for reasons other than cancer. But you must get the technique right.