Autotransplantation of Cryopreserved/Thawed Ovarian Tissue: Overview of Methods and Challenges

In recent years, an increasing number of women diagnosed with malignant or non-malignant diseases have been subjected to cytotoxic chemoradiotherapy. Women who face the possibility of premature or imminent ovarian failure caused by cytotoxic therapy may retain their fertility potential via ovarian tissue cryopreservation. Despite its advantages, this fertility preservation method for women at risk of losing reproductive function is considered experimental due to 1) a possible decrease in the ovarian follicular pool as a result of cryopreservation and thawing procedures (although this has been minimised by improved methods), or by ischemic damage occurring during ovarian transplantation; and 2) the risk of minimal residual disease (which is the most important factor). Although the indications for ovarian cryopreservation now extend beyond cancer, cancer survivors remain as the patient population who most commonly need this procedure. For these patients, the risk of minimal residual disease, which can be defined as reintroducing pre-existing cancer cells, is an important challenge for the application of this method. Even though the risk of reimplanting pre-existing cancer cells through ovarian transplantation is minimal or non-existent for most types of cancer, this risk must be ascertained according to cancer type and disease stage.