While advanced anti-cancer treatments reduce mortality in women, about 70 ∼ 100% of them suffer iatrogenic premature ovarian insufficiency (POI) as a result [Citation1]. In China, 4.82 million new cancer patients were diagnosed annually, ranking first globally [Citation2]. To safeguard the fertility of young patients at high risk of POI, ovarian tissue cryopreservation and transplantation (OTCT) has already been offered as a promising fertility preservation method in Western countries, especially for patients who need rapid fertility preservation without time for any ovarian stimulation. Although the first bank for ovarian tissue cryopreservation was established some years ago in the Beijing Obstetrics and Gynecology Hospital, Capital Medical University, and is still the only ovarian tissue cryobank in China, pregnancy with live birth as the most critical outcome to prove the efficacy of OTCT techniques, as used in this Chinese hospital, has not been reported. There are also no reports of any failed attempts to use this technique in this center. The paper in this issue by Ruan and colleagues reports a patient with myelodysplastic syndrome who gave birth to a healthy girl after OTCT, which is the first live birth in China using OTCT [Citation3]. This report really is a milestone for this populous country.
The prevalence of iatrogenic POI is growing with increasing survival rates of cancer patients, accounting for 65% of the identified causes of POI [Citation4]. The impact of iatrogenic POI is profound due to the sharp drop in ovarian hormones following damage to ovarian function caused by gonadotoxic treatments. The most unfortunate effect of iatrogenic POI is subfertility, as a substantial proportion of young patients facing anti-cancer treatments maintain reproductive intentions. Furthermore, POI is also associated with a significant increase in the risk of cardiovascular disease, osteoporosis, genitourinary symptoms, psychosexual dysfunction and early death. Therefore, preventing iatrogenic POI is a priority of concern.
Methods for fertility preservation (FP) include cryopreservation of oocytes, embryos and ovarian tissue. Oocyte cryopreservation is a mature FP technology but the pregnancy rate for each oocyte is relatively low, and it is recommended that at least 15 mature oocytes are frozen to achieve a higher pregnancy rate [Citation5]. However, it would take more than one cycle of ovulation induction to retrieve enough oocytes, which is too long for a patient in urgent need of cancer treatment. Besides, an unmarried woman cannot cryopreserve embryos for FP in most countries. Ovarian tissue cryopreservation is the only FP method for pre-pubertal girls and cancer patients who cannot delay treatment, storing thousands of early-stage follicles in the cortical strips. Furthermore, it is essential to emphasize that OTCT is an accurate way to prevent POI because ovarian function can be restored after ovarian tissue transplantation. For this reason and also for patients such as cervical cancer patients who have undergone hysterectomy, OTCT has great clinical significance. OTCT should therefore be the first choice of any surgical methods to prevent iatrogenic POI.
With increasing evidence of live births and return of endocrine function, OTCT is no longer considered experimental and is recommended by the American Society for Reproductive Medicine, the European Society of Human Reproduction and Embryology, and others. In a recent meta-analysis including 20 studies, the pregnancy rate was 37%, and the live birth rate was 28% after OTCT [Citation6].
The first ovarian tissue cryobank in China was established in the Beijing Obstetrics and Gynecology Hospital, Capital Medical University, with the help of international experts. In recent years, various xenotransplantation experiments and preclinical research projects have been conducted in this center to prove and to improve the technique's safety and efficacy [Citation7,Citation8]. Clinical application of OTCT was then confirmed by the New Technology Committee, the Ethics Committee, and the Expert Committee of the hospital. In 2016, the first transplantation in China was performed within that center in a cervical cancer patient whose ovarian function was restored 3 months after transplantation and was maintained for more than 5 years [Citation9]. Up to now, ten cases of OTCT have been successfully performed in this center, and ovarian activity was recovered in all cases after surgery [Citation10].
In conclusion, Professor Ruan’s paper reports the first live birth after OTCT in China, a milestone in reproductive medicine, and the significance is no less than or even more than the first IVF baby in China. Ovarian tissue cryopreservation cannot only preserve fertility, but can also restore the endocrine function of the ovaries, which should be the first choice to prevent iatrogenic POI. The safety and efficacy of OTCT have been proven by a large number of centers in the world, and OTCT has been used as routine technology in many countries. However, OTCT is just in the initial stage or even absent in some areas. The first ovarian tissue cryobank in China, located in Beijing Obstetrics and Gynecology Hospital, set an excellent example about how to establish an OTCT center according to high-level international standards, including the preparation of the facility, equipment, training, and standard operating procedures, resulting in a 100% success rate in 400 cases of cryopreservation and 10 cases of transplantation. China is a populous country, where the OTCT technique will achieve substantial social benefits in the near future. However, this success reported here from a case in China should highlight all over the world that the method should certainly no longer be described as ‘experimental’, but must be added into the routine of reproductive medicine options to preserve ovarian function and also fertility.
Potential conflict of interest
Thomas Rabe is a Guest Professor of the Beijing Obstetrics and Gynecology Hospital, Capital Medical University, China.
Source of funding
Nil.
References
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