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.

Early detection and aggressive chemotherapy/radiotherapy treatments have improved the long-term survival rates for many young women with various types of cancer. The structure of the human ovary is a crucial consideration in the potential success of cryopreservation. Four permeating cryoprotectants, glycerol (GLY), dimethyl sulfoxide (DMSO), ethylene glycol (EG), and propanediol (propylene glycol; PROH), have been used in human and animal ovarian tissue cryopreservation. In contrast to evaluation of outcomes from embryo or gamete cryopreservation, assessing the survival and viability of cryopreserved ovarian tissue poses specific challenges. There are only two morphometric studies of human ovarian tissue which assess cryopreservation, one of which is an evaluation of the most commonly used procedure using DMSO as a cryoprotectant and controlled rate cooling on tissue from six patients. Clinical evidence has established that fertilization and embryo development can occur in oocytes recovered from cryopreserved ovarian tissue transplanted at a heterotopic site.

Advances in the diagnosis and treatment of childhood, adolescent and adult cancer have increased the life expectancy of premenopausal women with the disease. Oncological indications for ovarian tissue cryopreservation are summarized. Patients undergoing oophorectomy for prophylaxis may potentially benefit from ovarian cryopreservation. There have been numerous reported cases of autotransplantation of cryopreserved ovarian tissue, either to an orthotopic or heterotopic site. Approximately one third of young women exposed to chemotherapy develop ovarian failure. It is our ethical responsibility to propose cryopreservation of ovarian tissue to all adolescents and young women under institutional review board (IRB) protocols having to undergo chemotherapy with alkylating agents. Research programs need to determine whether active angiogenesis can be induced to accelerate the process of neovascularization in grafted tissue, if isolated human follicles can be grafted or, indeed, if microvascular re-anatomosis of an entire cryopreserved ovary is a valuable option.

This chapter focuses on female fertility preservation procedures because of their complexity and peculiarities. Ovarian failure leads to the impossibility of childbearing apart from other problems related to the menopause, such as vasomotor, skeletal or cardiovascular alterations. Early menopause and infertility are two of the main consequences for patients treated with gonadotoxic agents. Gonadotoxicity, a decrease in ovarian activity, depends on several factors, including the age of the patient; the initial status of the ovaries; the treatment applied and cumulative doses; and the type of agent used. Ovarian tissue freezing for later autotransplantation is alternative for fertility preservation in women with oncological or non-oncological diseases. Any patient with a high risk of premature ovarian failure is a possible candidate for fertility preservation. Oocyte and ovarian tissue cryopreservation are useful as they overcome some of the disadvantages, ethical concerns and legal restrictions related to embryo cryopreservation.

Younger women with breast cancer are more likely to have poor prognostic features, such as larger tumor size, regional lymph node positivity, high nuclear grade, estrogen receptor negativity and inflammatory disease. Treatment for breast cancer can impact fertility for a variety of reasons, including a toxic effect of chemotherapy on ovarian follicles, advice to delay pregnancy due to concern for recurrence of disease and the recommendation for 5 years of adjuvant endocrine therapy for hormone-responsive disease. As a result of higher survival rates among women treated for breast cancer, there is an increasing emphasis on quality of life among survivors, and fertility preservation is a key issue among young women undergoing therapy for breast cancer. Embryo cryopreservation is considered the more effective approach to fertility preservation. The process of ovarian tissue cryopreservation involves freezing thin slices of the ovarian cortex.

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.