RESUMO
Ovarian tissue cryopreservation and subsequent autotransplantation is a successful technique for fertility preservation in oncological patients. However, there are concerns regarding safety, as the graft may contain malignant cells that could lead to the reintroduction of cancer. To circumvent this problem several experimental strategies are being pursued. This systematic review was conducted to provide an overview of the strategies aiming to safely use cryopreserved human ovarian tissue to restore fertility after cancer. Thirty-one studies were included, covering five different experimental strategies: (i) in-vitro maturation of oocytes, (ii) constructing an artificial ovary as a scaffold for reseeding pre-antral follicles, (iii) purging strategies aimed at the eradication of contaminating malignant cells, (iv) maturation of oocytes by xenotransplantation, and (v) stem cell-based oogenesis. These strategies to circumvent the reintroduction of cancer cells through ovarian tissue autotransplantation are being developed, but so far have not reached the stage of clinical trials. Further research is required to establish their risks and effectiveness while the ethical aspects associated with these strategies also need to be discussed. Despite the fact that these experimental procedures are still under development, they might provide safe fertility restoration options for oncological patients in the future.