[Ovarian tissue cryopreservation and transplantation: a review of clinical progress in fertility preservation].

With the increasing survival rates of cancer patients, the demand for fertility preservation in women has become increasingly prominent. Ovarian tissue cryopreservation and transplantation (OTCT) is an emerging fertility preservation technique that offers a unique advantage over embryo or oocyte cryopreservation, as it does not require ovarian stimulation. This makes it particularly suitable for prepubertal girls requiring urgent gonadotoxic therapy and reproductive-age women who cannot delay cancer treatment. Clinical evidence confirms that OTCT can effectively restore female fertility-especially the potential for natural conception-and restore ovarian endocrine function. The OTCT process involves key steps such as patient evaluation, tissue processing, cryopreservation, and transplantation. The patient's age at cryopreservation, ovarian reserve status, and prior exposure to gonadotoxic therapy significantly influence the outcomes of fertility preserva-tion. Optimal tissue preparation and the choice of cryopreservation method are critical for preserving ovarian tissue viability. During processing, the size of ovarian tissue fragments must be carefully controlled to balance freezing efficiency and post-transplantation viability, with adjustments based on individual patient factors. Slow freezing remains the mainstream clinical method, while vitrification is still considered experimental, with its efficacy and safety under ongoing investigation. The number, size, and transplantation site of ovarian tissue grafts impact their biological activity and functional outcomes. Both orthotopic and heterotopic transplantation can restore endocrine function, but orthotopic sites are superior for restoring fertility. A major safety concern in OTCT is the potential risk of reintroducing malignant or premalignant cells upon reimplantation. Innovative techniques such as in vitro maturation of oocytes and artificial ovaries are being explored to mitigate this risk. This review summarizes recent clinical advances in OTCT, with a focus on its indications, efficacy, implementation strategies, and safety profile, aiming to provide a reference for further research and clinical practice in this field.