[Fertility Preservation for Pediatric Brain Tumor Patients: Current Status and Challenges]

Fertility preservation treatment is becoming increasingly popular in Japan, but very few pediatric brain tumor patients have undergone this treatment even though such tumors are relatively common and affected patients are important candidates for fertility preservation. Fertility preservation treatments for girls include oocyte cryopreservation (OC) and ovarian tissue cryopreservation (OTC). However, OC requires transvaginal procedures and daily controlled ovarian stimulation, which can be difficult to implement, and OTC is still a new option, and there have been very few live births till now. For boys, sperm cryopreservation, including after testicular sperm extraction (TESE), is the only fertility preservation option. Among pediatric patients with brain tumors, boys are at higher risk of fertility loss (gonadal failure), especially those with germ cell tumors. Furthermore, more than half of the treatment protocols for atypical teratoid rhabdoid tumor or ependymoma have been shown to result in gonadal failure in both boys and girls. Currently, the reproductive outcomes of fertility preservation in pediatric brain tumor patients are unclear, and more cases need to be investigated.