Detection of minimal residual disease in ovarian tissue was carried out by histology, real-time quantitative polymerase chain reaction (RT-qPCR) and long-term xenografting. To avoid transferring malignant cells together with grafted ovarian tissue, ovarian follicles may be isolated from the surrounding tissue and then either cultured for in vitro follicle maturation or transplanted directly into the recipient. Transplantation of frozen-thawed isolated primordial follicles has been successfully carried out in mice, yielding normal offspring. After isolation and recovery of human follicles, the developmental capacity and viability of these isolated human follicles are evaluated after transplantation. New matrices have been developed based on hydrogels, foams or natural polymers which could be suitable to nestle the isolated follicles and form a kind of artificial ovary before grafting to the patient. This would allow patients at risk of ovarian metastasis to benefit also from ovarian tissue cryopreservation and transplantation.

Fertility preservation is now recognized as the most essential quality of life issue in young cancer survivors. This chapter discusses three urgent and critical problems involved with ovarian tissue cryopreservation and transplantation (cryoin-jury, ischemic tissue damage, cancer cell transmission). The risk of cancer cell transmission is a serious safety issue related to ovarian autotransplantation in cancer patient. There are three strategies, at least in theory, to mature follicles in frozen stored ovarian tissue: autotransplantation; xenotransplantation; and in-vitro culture. Recently, significant progress has been made in immature follicle culture techniques. As an alternative to ovarian tissue transplantation, whole ovary transplantation has been explored. In theory, whole intact ovary transplantation with vascular anastomosis can restore the full function of the ovary. The main challenge of whole ovary transplantation for fertility preservation is the development of effective cryotechnology for the whole organ.