Fertility preservation (FP) is a rapidly expanding field in reproductive medicine with still limited data on outcomes. FP aims to protect the fertility of children, women, and men who face the potential risk of fertility loss for various medical conditions, including but not limited to cancer and its gonadotoxic treatment forms. Therefore, it is crucial to provide evidence-based recommendations to assist health professionals in discussing FP options. Our aim was to provide a guideline for multidisciplinary medical staff in considering the availability of FP options and to help them decide whether to provide FP. The objective of any FP intervention is to minimize or eliminate primary disease burden and to ensure the maintenance or preserving reproductive health. Therefore, people who are at risk of losing fertility should be evaluated for and counseled about future reproductive risks. Embryo, oocyte, and ovarian tissue cryopreservation are the established FP options in adult females, with ovarian tissue cryopreservation the only option for prepubertal girls. A wide range of variables affect the choice of the FP strategy. These include age and ovarian reserve of women, the time available before the initiation of cancer treatment, pubertal status, and cancer type and stage. In males, sperm cryopreservation is a highly effective method in adolescent and adult males, while testicular tissue cryopreservation, which is experimental, is the only available option for prepubertal males. This review addressed the important clinical questions and provided answers for FP in females, males, and children according to the indications and availability of FP.

Background Non-growing follicles (NGF), constituting the ovarian reserve, are finite and established before birth. Ovarian tissue cryopreservation (OTC) often serves as a primary method of fertility preservation in child, adolescent and young adults (CAYA). Previous models had limited data on paediatrics and minimal methodological detail of follicle density (FD). This study aims to fill these gaps by developing a comprehensive model of FD in a CAYA cancer cohort without prior chemotherapy. Development of a centile chart could be of clinical value in predicting future fertility from cryopreserved ovarian tissue Methods The study recruited chemo-naïve patients aged 0-20 years who underwent OTC. A small proportion of tissue was fixed, processed, H&E-stained sections were scanned, and all follicles were counted and classified according to the NICHD proposed nomenclature. Follicle numbers within a cortical depth of 1 mm were used to determine FD for all follicular categories. NGF included primordial and transitional primordial follicles. Logarithmic linear regression models of FD according to age were described for each follicle category. JavaScript was used to create a web-based FD centile chart calculator. The project was approved under the Royal Children’s Hospital Human Research Ethics Committee project RCH HREC 2019.022. Results We recruited 134 patients, evenly distributed across the age range [0-5y: 28 (20.9%), 5.1-10y: 38 (28.4%), 10.1-15y: 40 (29.9%), 15.1-20y: 28 (20.9%)]. Mean NGF FD at birth was 35.51/mm2, halving every 6.3 years (p< 0.001). Growing follicles (primary to advanced follicles), have smaller FD at birth (0.9/mm2) p = 0.9 and have a longer half-life, >10 years (p< 0.001). An easy-to-use centile calculator web app has been developed. Conclusions Our study reports FD for a large population of CAYA chemo-naïve patients. We report half-life declines in FD across all types of follicles, with NGF showing the steepest decline. We introduce the first centile chart of follicle density, as well as a user-friendly web-based centile chart calculator, which will be helpful for clinicians.

Background Paediatric gynecology providers play leading roles in fertility preservation programs for prepubertal children, including male patients. While male adolescents may opt for sperm cryopreservation; procedural sperm retrieval may be possible for those who cannot collect a sample. This study aims to characterise predictive features of peripubertal and post pubertal males who had sperm successfully dissected from testicular tissue biopsies before gonadotoxic therapy. Methods At the Royal Children’s Hospital testicular tissue cryopreservation (TTCP) is approved under novel technologies governance. We performed a retrospective case review (2005–2023) of to describe age, Tanner stage, testicular volume, and diagnosis in peri/post-pubertal patients who had TTCP. Results Among 113 cases of TTCP in patients age 10-19 years: 31 (27.9%) had liquid cancer, 56 (49.6%) had solid cancer, and 24 (21.6%) non-cancer diagnoses. Of the 96 cases with sufficient records, 31 (32.2%) of patients had sperm dissected from testicular tissue. Of 58 cases with no prior gonadotoxic therapy for which we have complete records, sperm was found in 22 cases (37.9%) including in none who were genital Tanner stage 1, 33.3% who were genital Tanner stage 2, and 66.7%, 50.0%, and 87.5% of those who were Tanner stages 3,4 and 5, respectively. Additionally, sperm was dissected from 5.5% of males with testicular volume < 10 ml and 90.9% of those with testicular volumes >10mL (29 total). Sperm was dissected in 9.1%, 40.0%, 83.3%, and 50.0% of males aged 10-12, 12-14, 14-16, and 16 years and above, respectively. Conclusion While TTCP is experimental, testicular tissue dissection may offer a real chance of fertility restoration for peri and post pubertal patients who cannot provide sperm samples naturally. The best candidates are those who are Tanner stage 3 and above with testicular volume 10mL and above.

BACKGROUND:Remarkable progress in paediatric and adolescent fertility preservation (FP) has led to growing demand for services. However, best practice for gamete and gonadal tissue in paediatric and adolescent patients remains ill-defined. We explored the views of FP clinicians and laboratory staff on training needs for paediatric and adolescent FP procedures and services, the barriers across the FP pathway, and suggestions for improving service delivery. METHODS:Semi-structured interviews were conducted with multidisciplinary oncofertility experts from Australia and New Zealand. Data analysis of interview transcripts used the Framework Method. Results are reported with straight descriptions consistent with Qualitative Descriptive methods. RESULTS:Eighteen oncofertility clinicians and reproductive laboratory staff were interviewed. Paediatric surgeons viewed ovarian and testicular tissue harvesting within their scope of practice, though not gonadal tissue grafting. Education through direct observation and videos, and incorporation of oncofertility care into formalised surgical training programs was deemed important. Reproductive laboratory staff recommended that surgical training should include gonadal tissue harvesting techniques and guidance regarding adequate tissue volume removal. Reproductive laboratory staff requested bereavement training to better prepare them to support discussions with families. Oncofertility counselling and follow-up was not considered within scope of surgical practice by some surgeons and highlighted an unmet educational need by others. CONCLUSIONS:As FP procedures become more widespread, building of a surgical and laboratory workforce with the skills to implement care is important. A multidisciplinary approach, supported by clear governance frameworks outlining roles, responsibilities and best practice before, during, and after FP procedures, is essential to delivering high-quality, coordinated care.

STUDY QUESTION:How do age at oocyte cryopreservation (OC) and treatment indication affect the outcomes of OC cycles, particularly cumulative live birth rates (CLBR) per warm cycle? SUMMARY ANSWER:Age at OC significantly influenced CLBRs per warm cycle, with younger patients achieving higher success, while differences between treatment indications were not statistically significant. WHAT IS KNOWN ALREADY:OC is a well-established fertility preservation method, with success rates largely influenced by the woman's age at the time of freezing. However, limited data exist on how various medical and non-medical (elective) indications affect outcomes. STUDY DESIGN, SIZE, DURATION:This retrospective cohort study analyzed 4577 OC cycles from 3164 women treated between January 2014 and December 2023 at Melbourne IVF clinic, Australia. The primary outcome was CLBR per warm cycle. Secondary outcomes included the number of oocytes cryopreserved, oocyte survival rate upon warming, fertilization rate, good-quality embryo development, clinical pregnancy rate and miscarriage rate. PARTICIPANTS/MATERIALS, SETTING, METHODS:Data were obtained from electronic clinical records. OC cycles were categorized by age at oocyte retrieval and treatment indication: cancer diagnosis, other medical conditions and non-medical reasons. MAIN RESULTS AND THE ROLE OF CHANCE:The mean age at OC was lowest in the cancer group (31.3 ± 6.2 years) compared to other medical (34.4 ± 4.5 years) and non-medical (36.2 ± 3.1 years) groups (P < 0.01). During the study period, 647 warmed oocyte cycles were conducted. Oocyte survival rate was lower in the cancer group (81.5%) compared with other medical (85.3%) and non-medical (83.3%) groups (P < 0.01). The CLBR per started warm cycle was highest in patients under 35 years old (49.0%), followed by those aged 35-40 (36.8%) and lowest in patients over 40 (17.2%) (P < 0.01). Although CLBR appeared lower in the cancer group (35.6%) compared with other medical (36.0%) and non-medical (39.3%) groups, the differences did not reach statistical significance (P > 0.05). LIMITATIONS, REASONS FOR CAUTION:The study's retrospective design and the heterogeneity of medical indications in the "other medical" group are notable limitations. WIDER IMPLICATIONS OF THE FINDINGS:These findings reinforce the importance of early OC, when age is a controllable factor, to maximize fertility preservation outcomes. While cancer patients showed slightly lower success rates, OC remains a valuable option for these individuals. Further studies are needed to explore the impact of specific cancer types and treatment regimens on oocyte quality and reproductive outcomes. STUDY FUNDING/COMPETING INTEREST(S):No external funding was received for this study. The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER:Not applicable.

STUDY QUESTION Twenty years after the inception of the first fertility preservation programme for pre-pubertal boys, what are the current international practices with regard to cryopreservation of immature testicular tissue?SUMMARY ANSWER Worldwide, testicular tissue has been cryopreserved from over 3000 boys under the age of 18 years for a variety of malignant and non-malignant indications; there is variability in practices related to eligibility, clinical assessment, storage, and funding.WHAT IS KNOWN ALREADY For male patients receiving gonadotoxic treatment prior to puberty, testicular tissue cryopreservation may provide a method of fertility preservation. While this technique remains experimental, an increasing number of centres worldwide are cryopreserving immature testicular tissue and are approaching clinical application of methods to use this stored tissue to restore fertility. As such, standards for quality assurance and clinical care in preserving immature testicular tissue should be established.STUDY DESIGN, SIZE, DURATION A detailed survey was sent to 17 centres within the recently established ORCHID-NET consortium, which offer testicular tissue cryopreservation to patients under the age of 18 years. The study encompassed 60 questions and remained open from 1 July to 1 November 2022.PARTICIPANTS/MATERIALS, SETTING, METHODS Of the 17 invited centres, 16 completed the survey, with representation from Europe, Australia, and the USA. Collectively, these centres have cryopreserved testicular tissue from patients under the age of 18 years. Data are presented using descriptive analysis.MAIN RESULTS AND THE ROLE OF CHANCE Since the establishment of the first formal fertility preservation programme for pre-pubertal males in 2002, these 16 centres have cryopreserved tissue from 3118 patients under the age of 18 years, with both malignant (60.4%) and non-malignant (39.6%) diagnoses. All centres perform unilateral biopsies, while 6/16 sometimes perform bilateral biopsies. When cryopreserving tissue, 9/16 centres preserve fragments sized <= 5 mm3 with the remainder preserving fragments sized 6-20 mm3. Dimethylsulphoxide is commonly used as a cryoprotectant, with medium supplements varying across centres. There are variations in funding source, storage duration, and follow-up practice. Research, with consent, is conducted on stored tissue in 13/16 centres.LIMITATIONS, REASONS FOR CAUTION While this is a multi-national study, it will not encompass every centre worldwide that is cryopreserving testicular tissue from males under 18 years of age. As such, it is likely that the actual number of patients is even higher than we report. Whilst the study is likely to reflect global practice overall, it will not provide a complete picture of practices in every centre.WIDER IMPLICATIONS OF THE FINDINGS Given the research advances, it is reasonable to suggest that cryopreserved immature testicular tissue will in the future be used clinically to restore fertility. The growing number of patients undergoing this procedure necessitates collaboration between centres to better harmonize clinical and research protocols evaluating tissue function and clinical outcomes in these patients.STUDY FUNDING/COMPETING INTEREST(S) K.D. is supported by a CRUK grant (C157/A25193). R.T.M. is supported by an UK Research and Innovation (UKRI) Future Leaders Fellowship (MR/S017151/1). The MRC Centre for Reproductive Health at the University of Edinburgh is supported by MRC (MR/N022556/1). C.L.M. is funded by Kika86 and ZonMW TAS 116003002. A.M.M.v.P. is supported by ZonMW TAS 116003002. E.G. was supported by the Research Program of the Research Foundation-Flanders (G.0109.18N), Kom op tegen Kanker, the Strategic Research Program (VUB_SRP89), and the Scientific Fund Willy Gepts. J.-B.S. is supported by the Swedish Childhood Cancer Foundation (TJ2020-0026). The work of NORDFERTIL is supported by the Swedish Childhood Cancer Foundation (PR2019-0123; PR2022-0115), the Swedish Research Council (2018-03094; 2021-02107), and the Birgitta and Carl-Axel Rydbeck's Research Grant for Paediatric Research (2020-00348; 2021-00073; 2022-00317; 2023-00353). C.E is supported by the Health Department of the Basque Government (Grants 2019111068 and 2022111067) and Inocente Inocente Foundation (FII22/001). M.P.R. is funded by a Medical Research Council Centre for Reproductive Health Grant No: MR/N022556/1. A.F. and N.R. received support from a French national research grant PHRC No. 2008/071/HP obtained by the French Institute of Cancer and the French Healthcare Organization. K.E.O. is funded by the University of Pittsburgh Medical Center and the US National Institutes of Health HD100197. V.B-L is supported by the French National Institute of Cancer (Grant Seq21-026). Y.J. is supported by the Royal Children's Hospital Foundation and a Medical Research Future Fund MRFAR000308. E.G., N.N., S.S., C.L.M., A.M.M.v.P., C.E., R.T.M., K.D., M.P.R. are members of COST Action CA20119 (ANDRONET) supported by COST (European Cooperation in Science and Technology). The Danish Child Cancer Foundation is also thanked for financial support (C.Y.A.). The authors declare no competing interests.TRIAL REGISTRATION NUMBER N/A.

International and national oncofertility networks, including the US-led Oncofertility Consortium, FertiProtekt, and the Danish Network, have played pivotal roles in advancing the discipline of oncofertility over the last decade. Many other countries lack a shared approach to pediatric oncofertility health service delivery. This study aims to describe baseline oncofertility practices at Australian New Zealand Children's Haematology/Oncology Group centers in 2019-2021, describe binational priorities for care, and propose a 5-year action plan for best practice to be implemented by the newly formed Australian New Zealand Consortium in Children, Adolescents, and Young Adults (CAYA) Oncofertility (ANZCO).

Abstract For the same age, sex, and dosage, there can be significant variation in fertility outcomes in childhood cancer survivors. Genetics may explain this variation. This study aims to: (i) review the genetic contributions to infertility, (ii) search for pharmacogenomic studies looking at interactions of cancer treatment, genetic predisposition and fertility‐related outcomes. Systematic searches in MEDLINE Ovid, Embase Classic+Embase, and PubMed were conducted using the following selection criteria: (i) pediatric, adolescent, and young adult cancer survivors, below 25 years old at the time of diagnosis, (ii) fertility outcome measures after cancer therapy, (iii) genetic considerations. Studies were excluded if they were (i) conducted in animal models, (ii) were not published in English, (iii) editorial letters, (iv) theses. Articles were screened in Covidence by at least two independent reviewers, followed by data extraction and a risk of bias assessment using the Quality in Prognostic Studies tool. Eight articles were reviewed with a total of 29 genes. Outcome measures included sperm concentration, azoospermia, AMH levels, assessment of premature menopause, ever being pregnant or siring a pregnancy. Three studies included replication cohorts, which attempted replication of SNP findings for NPY2R, BRSK1, FANCI, CYP2C19, CYP3A4, and CYP2B6. Six studies were rated with a high risk of bias. Differing methods may explain a lack of replication, and small cohorts may have contributed to few significant findings. Larger, prospective longitudinal studies with an unbiased genome‐wide focus will be important to replicate significant results, which can be applied clinically.

Can an aurora kinase B/C inhibitor suppress AML cell line proliferation while not impacting on mouse follicles in vitro? Exposure to an aurora kinase inhibitor at a predetermined cytotoxic concentration suppressed AML cell proliferation but had no impact on subsequent follicle health in vitro. There is a risk that cryopreserved ovarian tissue from young women with a leukaemia diagnosis harbours leukemic cells, which on grafting could transfer disease. Novel chemotherapy agents, specifically aurora kinase inhibitors [ e.g. GSK 1070916 (GSK) ], target proteins involved in chromosomal alignment and segregation during mitosis and meiosis. It is anticipated that aurora kinase inhibitors would have an impact on the development of all somatic cells, including granulosa cells proliferating during follicle growth, however a previous study using ovarian tissue pieces indicated no impact on follicles. Primary and secondary follicles (diameter ≤ 100 µm) were manually dissected from adult mouse ovaries and embedded in an extracellular scaffold together with >1,000 AML cells. Individual follicles and AML cells were cultured for 7 days followed by exposure to GSK for 24 hours. GSK was removed by washing and the culture continued for another two days at which time cells were assessed for normal morphology and survival with live/dead staining (Calcein AM/ Ethidium Homodimer-1). The leukemic cell line OC1-AML-3 (DSMZ) was cultured in RPMI-1640 +10% FCS and routinely passaged as recommended. Cell proliferation and cytotoxicity were assessed using the Alamar Blue assay. 20% DMSO was used as a positive control in the cytotoxicity assays and live/dead evaluation. Follicles were cultured in αMEM, ITS, FSH, ascorbic acid and 10% FCS under oil in 5%CO2 : 95% air. Survival and growth were evaluated in two extracellular scaffolds; UltiMatrix and Hystem™-HP. Follicle survival and growth was better (p < 0.05) in UltiMatrix (84.7%; 61/72) compared to Hystem™-HP (72.0%;77/107) with an average increase of 20 µm in diameter at day 7. When OCI-AML-3 cells (0.7 x105/ml) were exposed to a range of concentrations of GSK (10nM to 10µM) for 24hr in an in vitro cytotoxicity assessment, survival was reduced to 0% at a concentration of 10µM. The 20% DMSO positive control also resulted in 0% survival. However, in the 3- dimensional scaffold culture, exposure to 10 µM GSK for 24hr resulted in a mean survival of OCI-AML-3 cells of 27% (100 cells counted/ well) which was similar to the 20% DMSO positive control (32%) and significantly different to the negative (no GSK) control (95%; p < 0.01). Follicles exposed to GSK appeared alive, emitting a strong green fluorescence for both oocyte and granulosa cells, although some of the surface follicular cells were dead. Live/dead staining of GSK exposed follicles was similar to follicles not exposed to GSK. In contrast, the majority of the follicular cells were dead following exposure to 20% DMSO. Due to whole mount assessment of the follicles for live/dead staining, it is difficult to determine whether the oocyte is alive. In scaffold culture some of the free cells present may be of follicular origin, potentially resulting in overestimation of the proportion of AML cells alive after GSK treatment. This 3- dimensional culture system, incorporating a follicle and a leukemic cell line within a scaffold provides a good model to assess the impact of chemotherapy on both cell types and could be applicable for human follicles. Not applicable

Abstract Study question Is the morphology of ovarian tissue from paediatric and adolescent girls similar to that from adults? Summary answer The presence of biovular follicles was more frequently observed in paediatric ovary than in the adult ovary. What is known already At birth there are approximately 1 million ovarian follicles that reduce to around 380,000 by puberty. Limited information is available on the morphology of paediatric and adolescent ovary but it is thought that, before the age of 6 years, the prepubertal ovary contains around 20% abnormal primordial follicles - more than in the adult ovary. Polyovular follicles are common in some animal species but rarely observed in the human adult ovary. They are thought to contribute to dizygotic twinning but the low frequency suggests they are not the sole origin. Study design, size, duration Haematoxylin and eosin stained sections of ovarian tissue were examined by 2 operators blinded to patient age. Follicles were classified according to modified Gougeon criteria. The proportions were compared with Fisher’s exact test and the frequency by one- way ANOVA. Participants/materials, setting, methods Ovarian cortex tissue was collected from a total of 71 children and adolescents and 85 adults undergoing fertility preservation. Those who had had previous chemotherapy and or pelvic irradiation were excluded. The population was divided into 30 children (<8 years, range 1 - 7.6 years), 25 peripubertal (8 - 14.1 years), 16 with confirmed pubertal status (13.7 - 16.6 years) and compared to 85 adults (18-36 years). Main results and the role of chance Biovular follicles were observed in 36.7% (11/30) of the ovarian tissue from children <8 years with, where present, an average frequency of 1/10.6 x103 follicles, in 28% (7/25) of the peripubertal girls with an average frequency of 1/11.9x103 follicles, and 18.7% (3/16) of the post pubertal girls with an average frequency of 1/7.7x103 follicles. In contrast, biovular follicles were rarely seen in the adult ovarian tissue examined (3.5%, 3/85) with an average frequency of 1/25x103 follicles. The observed frequency in all of the younger samples was significantly different to the adult (p < 0.001 <8 years, p < 0.001 peripubertal, p < 0.05 post pubertal) but not between the young age groups. In those samples with biovular follicles the frequency was not significantly different between any of the groups. An antral follicle was observed in only one case <8 years of age (1.4 years) - 3.3%, in 2 in the peripubertal (8%), in 4 of the post pubertal (25%) and in 9 of the adult ovarian cases (10.6%). The higher observed frequency in the post pubertal ovary compared to the <8 year was significantly different (p < 0.05). Limitations, reasons for caution Only a small sample of the ovary cortex was examined for each individual, which may be more representative of the young ovary than the adult. It is not possible to predict potential function from this analysis. Wider implications of the findings Although follicle numbers in the paediatric ovary are high, follicles with structural anomalies such as biovular follicles are also more frequently observed in the paediatric ovary than in the adult. It appears that the changes at puberty may cause the loss of these abnormal follicles. Trial registration number Not Applicable

To review elective oocyte vitrification at a single IVF unit over a 10-year period to facilitate the management of patient expectations. Retrospective analysis of 3280 elective oocyte vitrification cycles. Oocytes vitrified using Rapid I device in 15% ethylene glycol, 15% dimethyl sulfoxide and 0.5M sucrose. From January 2013 through December 2022, 3280 elective oocyte vitrification cycles were performed with 32621 oocytes vitrified. For oocytes vitrified between January 2013 and June 2017 the survival rate was 81.6% (701/859). In June 2017, an audit of the procedure indicated that some embryologists had been under filling the Rapid-I hole. Subsequent retraining and education on filling the Rapid-I resulted in a significant increase in survival to 91.5% (829/906) p<0.05. The outcomes of these warmed oocytes (vitrified post July 2017) were divided into age groups <38 and ≥38 (at the time of vitrification) and compared to age groups, from the same time, with fresh oocytes only. For vitrified oocytes from <38 patients, survival was 91.0% (454/499) with an average number of oocytes available for ICSI 11.4 vs 10.1 fresh (p=0.2); fertilisation was 64.8% vs 64.0% fresh (p=0.6) and foetal heart (FH) pregnancy rate was 42.3% (11/26) vs 41.0% (1801/4388) fresh (p=0.5). Similar survival was achieved with oocytes from the ≥38 patients; 92.1% (375/407) with an average number of oocytes for ICSI of 8.3 vs 6.7 fresh (p=0.04); fertilisation was 68.5% vs 60.3% fresh (p=0.9) and foetal heart (FH) pregnancy rate was 35.3% (12/34) vs 23.3% (954/4092) fresh (p=0.9). When vitrifying oocytes with the Rapid-I device, it is important to correctly fill the hole with solution. Patients undergoing oocyte vitrification should understand that not all their oocytes are likely to survive (loss rate of approximately 8.5%). Of the oocytes which do survive warming, fertilisation and pregnancy rates are similar to those of patients who did not vitrify oocytes.

Background Fertility preservation is an important healthcare focus in the paediatric and adolescent population when gonadotoxic treatments are required. Ovarian stimulation (OS) resulting in oocyte cryopreservation is a well-established fertility preservation option in the adult population. It’s utility, however, is little known in young patients. The purpose of this review was to synthesise the available literature on OS in patients ≤18 years old, to identify gaps in current research and provide suggestions for future research directions. Methods Using PRISMA guidelines, a systematic review of the literature was performed for all relevant full-text articles published in English in Medline, Embase, the Cochrane Library and Google Scholar databases. The search strategy used a combination of subject headings and generic terms related to the study topic and population. Two reviewers independently screened studies for eligibility, extracted data and assessed the risk of bias. Characteristics of the studies, objectives and key findings were extracted and summarised in a narrative synthesis. Results Database search and manual review identified 922 studies, 899 were eliminated based on defined exclusion criteria. Twenty-three studies were included and comprised 468 participants aged ≤18 years who underwent OS (median 15.2, range 7-18 years old). Only three patients were premenarchal, and four patients were on treatment to suppress puberty. Patients had OS for a broad range of indications including oncology treatment, transgender care and Turner syndrome. A total of 488 cycles of OS were completed, with all but 18 of these cycles (96.3%) successfully resulting in cryopreserved mature oocytes (median 10 oocytes, range 0-35). Fifty-three cycles (9.8%) were cancelled. Complications were rare (<1%). One pregnancy was reported from a female who had OS aged 17 years old. Conclusion This systematic review demonstrates that OS and oocyte cryopreservation is achievable in young females however there are only a few cases in the literature describing OS in premenarcheal children or those who have suppressed puberty. There is little proof that OS can lead to pregnancy in adolescents, and no proof that this can be achieved in premenarchal girls. Therefore it should be regarded as an innovative procedure for adolescents and experimental for premenarcheal girls. Systematic review registration https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=265705 , identifier CRD42021265705.

RESEARCH QUESTION:Is there potential for the detection of neuroblastoma malignancy in testicular tissue extracted for fertility preservation for prepubertal boys at the time of tissue freezing?DESIGN:This is a case report.RESULTS:A boy was diagnosed with primary localized left adrenal neuroblastoma, with complete resection of the tumour. During 6 months' surveillance, he developed a relapse in the left para-renal region with progression of molecular and chromosomal features into undifferentiated neuroblastoma. Before highly gonadotoxic treatment, testicular biopsy for fertility preservation was taken, from a clinically normal testis. Histopathological examination of the testicular biopsy revealed metastatic neuroblastoma.CONCLUSIONS:Metastatic neuroblastoma detected histologically in a clinically normal testis highlights the importance of routine histological examination at the time of testicular cryopreservation. The histological evaluation of gonadal tissue for potential malignant contamination before freezing should be mandatory, regardless of the malignancy diagnosis. Advances in sensitive molecular detection and in-vitro maturation are critically required to decrease future risk of disease recurrence in both solid and haematological malignancies.

BACKGROUND Ovarian tissue cryopreservation involves freezing and storing of surgically retrieved ovarian tissue in liquid or vapour nitrogen below -190 degrees C. The tissue can be thawed and transplanted back with the aim of restoring fertility or ovarian endocrine function. The techniques for human ovarian tissue freezing and transplantation have evolved over the last 20 years, particularly in the context of fertility preservation in pre-pubertal cancer patients. Fresh ovarian tissue transplantation, using an autograft or donor tissue, is a more recent development; it has the potential to preserve fertility and hormonal function in women who have their ovaries removed for benign gynaecological conditions. The techniques of ovarian tissue cryopreservation and transplantation have progressed rapidly since inception; however, the evidence on the success of this intervention is largely based on case reports and case series. OBJECTIVE AND RATIONALE The aim of this study was to systematically review the current evidence by incorporating study-level and individual patient-level meta-analyses of women who received ovarian transplants, including frozen-thawed transplant, fresh or donor graft. SEARCH METHODS The review protocol was registered with PROSPERO (CRD42018115233). A comprehensive literature search was performed using MEDLINE, EMBASE, CINAHL and Cochrane Central Register of Controlled Trials from database inception to October 2020. Authors were also contacted for individual patient data if relevant outcomes were not reported in the published manuscripts. Meta-analysis was performed using inverse-variance weighting to calculate summary estimates using a fixed-effects model. OUTCOMES The review included 87 studies (735 women). Twenty studies reported on >= 5 cases of ovarian transplants and were included in the meta-analysis (568 women). Fertility outcomes included pregnancy, live birth and miscarriage rates, and endocrine outcomes included oestrogen, FSH and LH levels. The pooled rates were 37% (95% CI: 32-43%) for pregnancy, 28% (95% CI: 24-34%) for live birth and 37% (95% CI: 30-46%) for miscarriage following frozen ovarian tissue transplantation. Pooled mean for pre-transplant oestrogen was 101.6 pmol/l (95% CI: 47.9-155.3), which increased post-transplant to 522.4 pmol/l (95% CI: 315.4-729; mean difference: 228.24; 95% CI: 180.5-276). Pooled mean of pre-transplant FSH was 66.4 IU/l (95% CI: 52.8-84), which decreased post-transplant to 14.1 IU/l (95% CI: 10.9-17.3; mean difference 61.8; 95% CI: 57-66.6). The median time to return of FSH to a value <25 IU/l was 19 weeks (interquartile range: 15-26 weeks; range: 0.4-208 weeks). The median duration of graft function was 2.5 years (interquartile range: 1.4-3.4 years; range: 0.7-5 years). The analysis demonstrated that ovarian tissue cryopreservation and transplantation could restore reproductive and hormonal functions in women. Further studies with larger samples of well-characterized populations are required to define the optimal retrieval, cryopreservation and transplantation processes. WIDER IMPLICATIONS Ovarian tissue cryopreservation and transplantation may not only be effective in restoring fertility but also the return of reproductive endocrine function. Although this technology was developed as a fertility preservation option, it may have the scope to be considered for endocrine function preservation.

Background: Recognised female fertility preservation strategies include oocyte and embryo cryopreservation. Ovarian tissue cryopreservation is no longer experimental, and the only option for children and pre-pubertal girls. Although testicular cryopreservation remains experimental for boys, it has the potential to evolve and provide a realistic opportunity for fertility in the future. The RWH/MIVF fertility preservation service has been preserving ovarian tissue since 1995. This service has been available to children, adolescent young adults (AYA) and adults about to receive gonadotoxic treatment for malignant and non-malignant conditions. In 2013, this service was extended to freezing testicular tissue for pre-pubertal and peri-pubertal males. Until 2019 these fertility preservation options have only been available to those undergoing procedures at Melbourne metropolitan hospitals. Young cancer patients seeking fertility preservation in regional or interstate areas, did not have this opportunity due to lack of access and resources. One approach to increasing patient access to Gonadal Tissue Cryopreservation (GTC), was to establish a national tissue retrieval and transport service. Aim: This paper describes the uptake of a GTC transport program at RWH, allowing rural and interstate oncology referral for transport, processing and storage of gonadal tissue in an acknowledged centre of excellence. Method: An information/education/instruction resource package was developed for fertility units Australia-wide, supported by a centralised GTC program coordinator. Referrals are fast tracked to eliminate any delay in treatment. Gonadal tissue is harvested at the referring hospital and transported to RWH for cryopreservation and storage, following methods established in other countries with a centralised service 1 – 3 . Results: To date, 40 ovarian and testicular tissue has been transported from all Australian states, and Northern Territory to RWH, including semen transported from a regional hospital where no fertility service was available. This service was made possible, and free of charge to those patients 13–30 yo with a cancer diagnosis, through a generous donation by Sony Foundation. Conclusion: Provision of a comprehensive fertility preservation service, including GTC, for young people, was not widely available until 2019. Gonadal tissue transport facilitates engagement and upskilling in oncofertility with extensive support from a centre of excellence, allowing expansion of patient and provider access to best-practice fertility preservation options, regardless of their geographic location and socio-economic status.

Women with β-thalassemia (BT) and sickle cell disease (SCD) have a high risk of infertility and premature ovarian insufficiency. Different fertility preserving strategies, including ovarian tissue cryopreservation (OTC) and oocyte cryopreservation has been considered, and healthy babies have been born after successful OTC and transplantation. We evaluated follicle number and follicle health in ovarian tissue from a cohort of BT and SCD patients who underwent OTC before the age of 18 years. Patients undergoing OTC from 2002 to 2019 were included. A total of 14 girls and adolescents with BT and four with SCD, aged 2.8–17.4 years at OTC were included together with a reference group of 43 girls and adolescents with non-anemia diseases considered to have normal ovaries aged 0.6–17.9 years at OTC. Ovarian follicle density was measured in cortex biopsies and compared to the reference group. Expression of proteins associated with follicular health was evaluated using immunohistochemistry. Follicles were detected in the ovarian cortex biopsies from all patients with BT and SCD. The follicle densities were within the 95% prediction interval of the reference group in all cases. A similar expression of six proteins essential for follicular health was detected using immunohistochemistry in BT, SCD, and references. OTC should be considered an option for young girls and adolescents with BT and SCD.