Recent advances in oncofertility care worldwide and in Japan

Abstract

Background: Oncofertility is a crucial facet of cancer supportive care. The publication of guidelines for the cryopreservation of oocytes and ovarian tissue is becoming increasingly prevalent in Japan and an updated overview is necessary.

Methods: In order to provide an updated overview of oncofertility care, original research and review articles were searched from the PubMed database and compared in order to present clinical care in Japan.

Results: In Western countries, various methods for ovarian stimulation, such as the combined use of aromatase inhibitors and random-start protocols, have been reported. Although ovarian tissue cryopreservation, mainly performed via the slow-freezing method, also has yielded >100 live births, the optimal indications and procedures for the auto-transplantation of cryopreserved tissue have been under investigation. In Japan, however, vitrification is prevalent for ovarian tissue cryopreservation, although its efficacy has not yet been established. The quality of network systems for providing oncofertility care in Japan varies greatly, based on the region.

Conclusion: There remain many issues in the optimization of oncofertility care in Japan. Along with the regional oncofertility networks, the creation of "oncofertility navigators" from healthcare providers who are familiar with oncofertility, such as nurses, psychologists, and embryologists, could be useful for supplementing oncofertility care coordination, overcoming the issues in individual regions.

Keywords: cryopreservation; fertility preservation; oocytes; ovary; survivorship.

Figure 1

Usages of cryopreserved ovarian tissue. The solid lines represent clinically applied methods that have achieved pregnancies and births, while the dotted lines represent methods that are in the research stage. IVM, in vitro maturation

Figure 2

Japanese hospitals and clinics that are engaged in cancer treatment (adult and pediatric), assisted reproductive technology (ART), and fertility preservation (FP). The numbers represent the number of hospitals and clinics belonging to each population. Japan has ~179 000 hospitals and clinics.105 Cancer treatment also is performed at hospitals and clinics other than at Ministry of Health, Labour and Welfare (MHLW)‐designated cancer hospitals, whereas ART and FP (red) are performed only at hospitals and clinics that are registered with the Japan Society of Obstetrics and Gynecology (JSOG)

Figure 3

Distribution of the fertility preservation hospitals and clinics in Japan. The red pins represent the hospitals or clinics that cryopreserve both ovarian tissue and unfertilized oocytes, while the orange pins represent the hospitals or clinics that only cryopreserve unfertilized oocytes. The figure demonstrates the concentration of fertility preservation hospitals and clinics in the major metropolitan areas (insets) and the dearth of fertility preservation hospitals and clinics along the Sea of Japan coast and in the Tohoku (north‐eastern) region