Safety and usefulness of cryopreservation of ovarian tissue to preserve fertility: a 12-year retrospective analysis

Abstract

Study question: Do the benefits of ovarian tissue cryopreservation outweigh the risks for patients seeking to preserve fertility before gonadotoxic treatment in various indications?

Summary answer: In >90% of the patients undergoing cryopreservation of ovarian tissue, oncological treatment was associated with a reduced ovarian reserve and in 30% of patients, premature ovarian failure (POF) occurred within 5 years.

What is known already: Ovarian tissue cryopreservation is an effective fertility preservation option, especially for pre-pubertal patients and patients who have a short time between diagnosis of a disease and gonadotoxic treatment.

Study design, setting, duration: This study retrospectively analysed ovarian function and fertility recovery rates, as well as ovarian tissue characteristics, of patients who underwent ovarian tissue cryopreservation at Erasme Hospital between 1999 and 2011.

Participants/materials, settings, methods: A total of 225 patients referred from 15 Belgian oncological units underwent cryopreservation of ovarian tissue before gonadotoxic therapy for malignant or benign diseases. There were 28 patients (12.4%) who died during follow-up due to recurrence of disease. One severe adverse event occurred during anaesthesia for ovarian tissue collection, leading to the death of the patient. Ovarian function and fertility outcomes were available for 114 patients including 13 girls who were pre-pubertal at the time of the procedure. Eight patients had undergone ovarian tissue transplantation in order to restore their fertility after remission of the disease.

Main results and the role of chance: Breast cancer and haematological disease were the most frequent indications for ovarian tissue cryopreservation. Overall, 90% of post-pubertal patients were diagnosed with poor ovarian reserve (AMH < 0.5 ng/ml) after a mean of 50 months of follow-up (11-125 months), including 30% with POF (FSH > 40 IU/ml). Breast cancer patients had a lower rate of POF than did post-pubertal patients with haematological diseases (11 versus 34.5%, respectively), despite the older age (mean 31 versus 23.5 years old, respectively) of the breast cancer patients. Ovarian function returned in 71 post-pubertal patients without the need for grafts of cryopreserved tissue. Spontaneous pregnancies were reported for 33 of them, leading to 34 live births. Among the 13 pre-pubertal patients who reached pubertal age during the follow-up, 10 had POF. Eight patients received cryopreserved ovarian grafts to reverse POF and three of them have already become pregnant.

Limitations, reasons for caution: This study is a retrospective analysis. The cohort was not compared with a control group of patients who did not undergo the procedure.

Wider implications of the findings: After careful evaluation of the surgical risks, ovarian tissue cryopreservation can be proposed as an efficient option to preserve the fertility of children and young adults facing gonadotoxic therapies. However, alternative procedures such as oocyte or embryo cryopreservation should be considered as first options especially for older patients or if there is high risk of neoplastic cells within the ovaries.

Study funding/competing interest: This study was supported by the Télévie, FNRS-FRSM and Fondation Belge contre le cancer. There are no competing interests to report.

Keywords: cancer; cryopreservation; fertility preservation; in vitro maturation; ovarian tissue.