THE CRYOPRESERVATION OF OVARIAN TISSUE AS A STRATEGY FOR PRESERVING THE FERTILITY OF CANCER-PATIENTS

The cryopreservation of ovarian tissue is a promising new method for c onserving the fecundity of young cancer patients from the sterilizing effects of chemotherapy and/or radiotherapy. In murine and ovine studi es the orthotopic insertion of frozen-thawed ovarian grafts into steri lized hosts has resulted in the birth of healthy offspring. Examinatio n of human ovarian tissue after cryopreservation has shown that substa ntial numbers of morphologically normal and viable primordial follicle s survive freeze-thawing. To date however, there is no efficient proce dure for using the frozen-banked tissue to restore fertility to patien ts with ovarian failure. Autografting at an orthotopic or heterotopic site has the greatest potential for success but there is concern that the technique may reintroduce malignant cells to patients in remission from disease. Follicle isolation from the thawed tissue and growth to maturity in vitro is a preferable option but at present the technique is in its infancy. This review presents past and present research in the field of ovarian tissue cryopreservation and explores the possible strategies by which frozen-banked tissue from cancer patients could b e used to restore fertility.