A short report on current fertility preservation strategies for boys

A 10-year experience in testicular tissue cryopreservation for boys under 18 years of age: What can be learned from 350 cases?

BACKGROUND

A growing number of centers worldwide are preserving testicular tissue (TT) of young boys at risk of fertility loss to preserve their fertility. Data in this regard are scarce and experience sharing is essential to the optimization of the process.

OBJECTIVES

This report of our 10-year activity of pediatric fertility preservation (FP) has the objective to (1) improve knowledge regarding the feasibility, acceptability, safety, and potential usefulness of the procedure; (2) analyze the impact of chemotherapy on spermatogonia in the cryopreserved TT.

MATERIALS AND METHODS

For this retrospective study of data prospectively recorded, we included all boys under 18 years of age referred to the FP consultation of our academic network between October 2009 and December 2019. Characteristics of patients and cryopreservation of testicular tissue (CTT) were extracted from the clinical database. Univariate and multivariate analyses were used to assess factors associated with the risk of absence of spermatogonia in the TT.

RESULTS

Three hundred and sixty-nine patients (7.2 years; 0.5-17.0) were referred to the FP consultation for malignant (70%) or non-malignant (30%) disease, of whom 88% were candidates for CTT, after a previous chemotherapy exposure (78%). The rate of recorded immediate adverse events was 3.5%, with painful episodes dominating. Spermatogonia were detected in the majority of TTs: 91.1% of those exposed to chemotherapy and 92.3% of those not exposed (p = 0.962). In multivariate analysis, the risk of absence of spermatogonia was almost three-fold higher in boys > 10 years of age ([OR] 2.74, 95% CI 1.09-7.26, p = 0.035) and four-fold higher in boys exposed to alkylating agents prior to CTT ([OR] 4.09, 95% CI 1.32-17.94, p = 0.028).

DISCUSSION/CONCLUSION

This large series of pediatric FP shows that this procedure is well accepted, feasible, and safe in the short term, strengthening its place in the clinical care pathway of young patients requiring a highly gonadotoxic treatment. Our results demonstrate that CTT post-chemotherapy does not impair the chance to preserve spermatogonia in the TT except when the treatment includes alkylating agents. More data on post-CTT follow-up are still required to ensure the long-term safety and usefulness of the procedure.

Impact of low- or moderate-risk gonadotoxic chemotherapy prior to testicular tissue freezing on spermatogonia quantity in human (pre)pubertal testicular tissue

STUDY QUESTION

What is the impact of low- or moderate-risk gonadotoxic chemotherapy received prior to testicular tissue freezing (TTF), and of the cancer itself, on spermatogonia quantity in testicular tissue from (pre)pubertal boys?

SUMMARY ANSWER

Vincristine, when associated with alkylating agents, has an additional adverse effect on spermatogonia quantity, while carboplatin has no individual contribution to spermatogonia quantity, in testicular tissue of (pre)pubertal boys, when compared to patients who have received non-alkylating chemotherapy.

WHAT IS KNOWN ALREADY

The improved survival rates after cancer treatment necessitate the inclusion of fertility preservation procedures as part of the comprehensive care for patients, taking into consideration their age. Sperm cryopreservation is an established procedure in post-pubertal males while the TTF proposed for (pre)pubertal boys remains experimental. Several studies exploring testicular tissue of (pre)pubertal boys after TTF have examined the tubular fertility index (TFI, percentage of seminiferous tubule cross-sections containing spermatogonia) and the number of spermatogonia per seminiferous tubule cross-section (S/T). All studies have demonstrated that TFI and S/T always decrease after the introduction of chemotherapeutic agents, especially those which carry high gonadotoxic risks such as alkylating agents.

STUDY DESIGN, SIZE, DURATION

Testicular tissue samples from 79 (pre)pubertal boys diagnosed with cancer (from 6 months to 16 years of age) were cryopreserved between May 2009 and June 2014. Their medical diagnoses and previous chemotherapy exposures were recorded. We examined histological sections of (pre)pubertal testicular tissue to elucidate whether the chemotherapy or the primary diagnosis affects mainly TFI and S/T.

PARTICIPANTS/MATERIALS, SETTING, METHODS

(Pre)pubertal boys with cancer diagnosis who had been offered TTF prior to conditioning treatment for hematopoietic stem cell transplantation were included in the study. All the patients had previously received chemotherapy with low- or moderate-risk for future fertility. We have selected patients for whom the information on the chemotherapy received was complete. The quantity of spermatogonia and quality of testicular tissue were assessed by both morphological and immunohistochemical analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

A significant reduction in the number of spermatogonia was observed in boys treated with alkylating agents. The mean S/T values in boys exposed to alkylating agents were significantly lower compared to boys exposed to non-alkylating agents (P = 0.018). In contrast, no difference was observed for patients treated with carboplatin as the sole administered alkylating agent compared to the group of patients exposed to non-alkylating agents. We observed an increase of S/T with age in the group of patients who did not receive any alkylating agent and a decrease of S/T with age when patients received alkylating agents included in the cyclophosphamide equivalent dose (CED) formula (r = 0.6166, P = 0.0434; r = -0.3759, P = 0.0036, respectively). The TFI and S/T decreased further in the group of patients who received vincristine in combination with alkylating agents (decrease of 22.4%, P = 0.0049 and P < 0.0001, respectively), but in this group the CED was also increased significantly (P < 0.0001). Multivariate analysis, after CED adjustment, showed the persistence of a decrease in TFI correlated with vincristine administration (P = 0.02).

LIMITATIONS, REASONS FOR CAUTION

This is a descriptive study of testicular tissues obtained from (pre)pubertal boys who were at risk of infertility. The study population is quite heterogeneous, with a small number of patients in each sub-group. Our results are based on comparisons between patients receiving alkylating agents compared to patients receiving non-alkylating agents rather than chemotherapy-naive patients. The French national guidelines for fertility preservation in cancer patients recommend TTF before highly gonadotoxic treatment. Therefore, all the patients had received low- or moderate-risk gonadotoxic chemotherapy before TTF. Access to testicular tissue samples from chemotherapy-naive patients with comparable histological types of cancer was not possible. The functionality of spermatogonia and somatic cells could not be tested by transplantation or in vitro maturation due to limited sample sizes.

WIDER IMPLICATIONS OF THE FINDINGS

This study summarizes the spermatogonial quantity of (pre)pubertal boys prior to TTF. We confirmed a negative correlation between the cumulative exposure to alkylating agents and spermatogonial quantity. In addition, the synergistic use of vincristine in combination with alkylating agents showed a cumulative deleterious effect on the TFI. For patients for whom fertility preservation is indicated, TTF should be proposed for chemotherapy with a predicted CED above 4000 mg/m2. However, the data obtained from vincristine and carboplatin use should be confirmed in a subsequent study including more patients.

STUDY FUNDING/COMPETING INTEREST(S)

This study had financial support from a French national research grant PHRC No. 2008/071/HP obtained by the French Institute of Cancer and the French Healthcare Organization. The sponsors played no role in the study. The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

A comprehensive review and update on human fertility cryopreservation methods and tools

The broad conceptualization of fertility preservation and restoration has become already a major concern in the modern western world since a large number of individuals often face it in the everyday life. Driven by different health conditions and/or social reasons, a variety of patients currently rely on routinely and non-routinely applied assisted reproductive technologies, and mostly on the possibility to cryopreserve gametes and/or gonadal tissues for expanding their reproductive lifespan. This review embraces the data present in human-focused literature regarding the up-to-date methodologies and tools contemporarily applied in IVF laboratories' clinical setting of the oocyte, sperm, and embryo cryopreservation and explores the latest news and issues related to the optimization of methods used in ovarian and testicular tissue cryopreservation.

Pediatric oncofertility care in limited versus optimum resource settings: results from 39 surveyed centers in Repro-Can-OPEN Study Part I & II

PURPOSE

As a secondary report to elucidate the diverse spectrum of oncofertility practices for childhood cancer around the globe, we present and discuss the comparisons of oncofertility practices for childhood cancer in limited versus optimum resource settings based on data collected in the Repro-Can-OPEN Study Part I & II.

METHODS

We surveyed 39 oncofertility centers including 14 in limited resource settings from Africa, Asia, and Latin America (Repro-Can-OPEN Study Part I), and 25 in optimum resource settings from the USA, Europe, Australia, and Japan (Repro-Can-OPEN Study Part II). Survey questions covered the availability of fertility preservation and restoration options offered in case of childhood cancer as well as their degree of utilization.

RESULTS

In the Repro-Can-OPEN Study Part I & II, responses for childhood cancer and calculated oncofertility scores showed the following characteristics: (1) higher oncofertility scores in optimum resource settings than in limited resource settings for ovarian and testicular tissue cryopreservation; (2) frequent utilization of gonadal shielding, fractionation of anticancer therapy, oophoropexy, and GnRH analogs; (3) promising utilization of oocyte in vitro maturation (IVM); and (4) rare utilization of neoadjuvant cytoprotective pharmacotherapy, artificial ovary, in vitro spermatogenesis, and stem cells reproductive technology as they are still in preclinical or early clinical research settings.

CONCLUSIONS

Based on Repro-Can-OPEN Study Part I & II, we presented a plausible oncofertility best practice model to help optimize care for children with cancer in various resource settings. Special ethical concerns should be considered when offering advanced and innovative oncofertility options to children.

The Role of Promyelocytic Leukemia Zinc Finger (PLZF) and Glial-Derived Neurotrophic Factor Family Receptor Alpha 1 (GFRα1) in the Cryopreservation of Spermatogonia Stem Cells

The cryopreservation of spermatogonia stem cells (SSCs) has been widely used as an alternative treatment for infertility. However, cryopreservation itself induces cryoinjury due to oxidative and osmotic stress, leading to reduction in the survival rate and functionality of SSCs. Glial-derived neurotrophic factor family receptor alpha 1 (GFRα1) and promyelocytic leukemia zinc finger (PLZF) are expressed during the self-renewal and differentiation of SSCs, making them key tools for identifying the functionality of SSCs. To the best of our knowledge, the involvement of GFRα1 and PLZF in determining the functionality of SSCs after cryopreservation with therapeutic intervention is limited. Therefore, the purpose of this review is to determine the role of GFRα1 and PLZF as biomarkers for evaluating the functionality of SSCs in cryopreservation with therapeutic intervention. Therapeutic intervention, such as the use of antioxidants, and enhancement in cryopreservation protocols, such as cell encapsulation, cryoprotectant agents (CPA), and equilibrium of time and temperature increase the expression of GFRα1 and PLZF, resulting in maintaining the functionality of SSCs. In conclusion, GFRα1 and PLZF have the potential as biomarkers in cryopreservation with therapeutic intervention of SSCs to ensure the functionality of the stem cells.

Perspectives: Methods for Evaluating Primate Spermatogonial Stem Cells

Mammalian spermatogenesis is a complex, highly productive process generating millions of sperm per day. Spermatogonial stem cells (SSCs) are at the foundation of spermatogenesis and can either self-renew, producing more SSCs, or differentiate to initiate spermatogenesis and produce sperm. The biological potential of SSCs to produce and maintain spermatogenesis makes them a promising tool for the treatment of male infertility. However, translating knowledge from rodents to higher primates (monkeys and humans) is challenged by different vocabularies that are used to describe stem cells and spermatogenic lineage development in those species. Furthermore, while rodent SSCs are defined by their biological potential to produce and maintain spermatogenesis in a transplant assay, there is no equivalent routine and accessible bioassay to test monkey and human SSCs or replicate their functions in vitro. This chapter describes progress characterizing, isolating, culturing, and transplanting SSCs in higher primates.

What should be done in terms of fertility preservation for patients with cancer? The French 2021 guidelines

AIM

To provide practice guidelines about fertility preservation (FP) in oncology.

METHODS

We selected 400 articles after a PubMed review of the literature (1987-2019).

RECOMMENDATIONS

Any child, adolescent and adult of reproductive age should be informed about the risk of treatment gonadotoxicity. In women, systematically proposed FP counselling between 15 and 38 years of age in case of treatment including bifunctional alkylating agents, above 6 g/m2 cyclophosphamide equivalent dose (CED), and for radiation doses on the ovaries ≥3 Gy. For postmenarchal patients, oocyte cryopreservation after ovarian stimulation is the first-line FP technique. Ovarian tissue cryopreservation should be discussed as a first-line approach in case of treatment with a high gonadotoxic risk, when chemotherapy has already started and in urgent cases. Ovarian transposition is to be discussed prior to pelvic radiotherapy involving a high risk of premature ovarian failure. For prepubertal girls, ovarian tissue cryopreservation should be proposed in the case of treatment with a high gonadotoxic risk. In pubertal males, sperm cryopreservation must be systematically offered to any male who is to undergo cancer treatment, regardless of toxicity. Testicular tissue cryopreservation must be proposed in males unable to cryopreserve sperm who are to undergo a treatment with intermediate or severe risk of gonadotoxicity. In prepubertal boys, testicular tissue preservation is: - recommended for chemotherapy with a CED ≥7500 mg/m2 or radiotherapy ≥3 Gy on both testicles. - proposed for chemotherapy with a CED ≥5.000 mg/m2 or radiotherapy ≥2 Gy. If several possible strategies, the ultimate choice is made by the patient.

Fertility after Curative Therapy for Sickle Cell Disease: A Comprehensive Review to Guide Care

Curative therapy for sickle cell disease (SCD) currently requires gonadotoxic conditioning that can impair future fertility. Fertility outcomes after curative therapy are likely affected by pre-transplant ovarian reserve or semen analysis parameters that may already be abnormal from SCD-related damage or hydroxyurea treatment. Outcomes are also likely affected by the conditioning regimen. Conditioning with myeloablative busulfan and cyclophosphamide causes serious gonadotoxicity particularly among post-pubertal females. Reduced-intensity and non-myeloablative conditioning may be acutely less gonadotoxic, but more short and long-term fertility outcome data after these approaches is needed. Fertility preservation including oocyte/embryo, ovarian tissue, sperm, and experimental testicular tissue cryopreservation should be offered to patients with SCD pursing curative therapy. Regardless of HSCT outcome, longitudinal post-HSCT fertility care is required.

Male fertility preservation and restoration strategies for patients undergoing gonadotoxic therapies†

Medical treatments for cancers or other conditions can lead to permanent infertility. Infertility is an insidious disease that impacts not only the ability to have a biological child but also the emotional well-being of the infertile individuals, relationships, finances, and overall health. Therefore, all patients should be educated about the effects of their medical treatments on future fertility and about fertility preservation options. The standard fertility preservation option for adolescent and adult men is sperm cryopreservation. Sperms can be frozen and stored for a long period, thawed at a later date, and used to achieve pregnancy with existing assisted reproductive technologies. However, sperm cryopreservation is not applicable for prepubertal patients who do not yet produce sperm. The only fertility preservation option available to prepubertal boys is testicular tissue cryopreservation. Next-generation technologies are being developed to mature those testicular cells or tissues to produce fertilization-competent sperms. When sperm and testicular tissues are not available for fertility preservation, inducing pluripotent stem cells derived from somatic cells, such as blood or skin, may provide an alternative path to produce sperms through a process call in vitro gametogenesis. This review describes standard and experimental options to preserve male fertility as well as the experimental options to produce functional spermatids or sperms from immature cryopreserved testicular tissues or somatic cells.

Spermatogonial Stem Cell-Based Therapies: Taking Preclinical Research to the Next Level

Fertility preservation via biobanking of testicular tissue retrieved from testicular biopsies is now generally recommended for boys who need to undergo gonadotoxic treatment prior to the onset of puberty, as a source of spermatogonial stem cells (SSCs). SSCs have the potential of forming spermatids and may be used for therapeutic fertility approaches later in life. Although in the past 30 years many milestones have been reached to work towards SSC-based fertility restoration therapies, including transplantation of SSCs, grafting of testicular tissue and various in vitro and ex vivo spermatogenesis approaches, unfortunately, all these fertility therapies are still in a preclinical phase and not yet available for patients who have become infertile because of their treatment during childhood. Therefore, it is now time to take the preclinical research towards SSC-based therapy to the next level to resolve major issues that impede clinical implementation. This review gives an outline of the state of the art of the effectiveness and safety of fertility preservation and SSC-based therapies and addresses the hurdles that need to be taken for optimal progression towards actual clinical implementation of safe and effective SSC-based fertility treatments in the near future.

Fertility preservation in boys facing gonadotoxic cancer therapy

Patient survival following childhood cancer has increased with contemporary radiation and chemotherapy techniques. However, gonadotoxicity associated with treatments means that infertility is a common consequence in survivors. Novel fertility preservation options are emerging, but knowledge about these options amongst urologists and other medical professionals is lacking. Pre-pubertal boys generally do not produce haploid germ cells. Thus, strategies for fertility preservation require cryopreservation of tissue containing spermatogonial stem cells (SSCs). Few centres worldwide routinely offer this option and fertility restoration (including testicular tissue engraftment, autotransplantation of SSCs and in vitro maturation of SSCs to spermatozoa) post-thaw is experimental. In pubertal boys, the main option for fertility preservation is masturbation and cryopreservation of the ejaculate. Assisted ejaculation using penile vibratory stimulation or electroejaculation and surgical sperm retrieval can be used in a sequential manner after failed masturbation. Physicians should inform boys and parents about the gonadotoxic effects of cancer treatment and offer fertility preservation. Preclinical experience has identified challenges in pre-pubertal fertility preservation, but available options are expected to be successful when today's pre-pubertal boys with cancer become adults. By contrast, fertility preservation in pubertal boys is clinically proven and should be offered to all patients undergoing cancer treatment.

Testicular Tissue Banking for Fertility Preservation in Young Boys: Which Patients Should Be Included?

Due to the growing number of young patients at risk of germ cell loss, there is a need to preserve spermatogonial stem cells for patients who are not able to bank spermatozoa. Worldwide, more and more clinics are implementing testicular tissue (TT) banking programs, making it a novel, yet indispensable, discipline in the field of fertility preservation. Previously, TT cryopreservation was predominantly offered to young cancer patients before starting gonadotoxic chemo- or radiotherapy. Nowadays, most centers also bank TT from patients with non-malignant conditions who need gonadotoxic conditioning therapy prior to hematopoietic stem cell (HSCT) or bone marrow transplantation (BMT). Additionally, some centers include patients who suffer from genetic or developmental disorders associated with prepubertal germ cell loss or patients who already had a previous round of chemo- or radiotherapy. It is important to note that the surgical removal of TT is an invasive procedure. Moreover, TT cryopreservation is still considered experimental as restoration methods are not yet clinically available. For this reason, TT banking should preferably only be offered to patients who are at significant risk of becoming infertile. In our view, TT cryopreservation is recommended for young cancer patients in need of high-risk chemo- and/or radiotherapy, regardless of previous low-risk treatment. Likewise, TT banking is advised for patients with non-malignant disorders such as sickle cell disease, beta-thalassemia, and bone marrow failure, who need high-risk conditioning therapy before HSCT/BMT. TT retrieval during orchidopexy is also proposed for patients with bilateral cryptorchidism. Since patients with a medium- to low-risk treatment generally maintain their fertility, TT banking is not advised for this group. Also for Klinefelter patients, TT banking is not recommended as it does not give better outcomes than a testicular sperm extraction later in life.

Assessment of the architecture and integrity of frozen-thawed testicular tissue from (pre)pubertal boys with cancer

BACKGROUND

Testicular tissue freezing is proposed for fertility preservation to (pre)pubertal boys with cancer before highly gonadotoxic treatment. Studies accurately comparing human (pre)pubertal testicular tissue quality before freezing and after thawing are exceptional. No study has reported this approach in a systematic manner and routine care.

OBJECTIVES

To assess the impact of a control slow freezing protocol on testicular tissue architecture and integrity of (pre)pubertal boys after thawing.

MATERIALS AND METHODS

(Pre)pubertal boys (n = 87) with cancer from 8 Reproductive Biology Laboratories of the French CECOS network benefited from testicular tissue freezing before hematopoietic stem cell transplantation. Seminiferous tubule cryodamage was determined histologically by scoring morphological alterations and by quantifying intratubular spermatogonia and the expression of DNA replication and repair marker in frozen-thawed testicular fragments.

RESULTS

A significant increase in nuclear and epithelial score alterations was observed after thawing (p < 0.0001). The global lesional score remained lower than 1.5 and comparable to fresh testicular tissue. The number of intratubular spermatogonia and the expression of DNA replication and repair marker in spermatogonia and Sertoli cells did not vary significantly after thawing. These data showed the good preservation of the seminiferous tubule integrity and architecture after thawing, as previously reported in our studies performed in prepubertal mice and rats.

DISCUSSION

The current study reports, for the first time, the development of a semi-quantitative analysis of cryodamage in human (pre)pubertal testicular tissue, using a rapid and useful tool that can be proposed in routine care to develop an internal and external quality control for testicular tissue freezing. This tool can also be used when changing one or several parameters of the freezing-thawing procedure.

CONCLUSION

Control slow freezing protocol without seeding maintains the seminiferous tubule architecture and integrity, the concentration of spermatogonia and the expression of DNA replication and repair marker in spermatogonia and Sertoli cells after thawing.

Predicting successful sperm retrieval in transfeminine adolescents after testicular biopsy

PURPOSE

Increasing numbers of transgender adolescents are receiving gender-affirming treatments (GAT). Given GAT can impair reproductive function, clinical guidelines advise prior counselling regarding fertility preservation (FP). For transgender adults assigned male at birth, FP is usually achieved via a masturbatory sample and sperm cryopreservation. This is less straightforward in transgender adolescents, since they may not be developmentally ready to masturbate and/or masturbation may cause unacceptable gender dysphoria. Testicular biopsy represents an alternative method for sperm retrieval in these adolescents, but for those in early/mid puberty, it is difficult to predict whether sperm will be found. The purpose of this study was therefore to identify factors that predict successful sperm retrieval for cryopreservation via testicular biopsy.

METHODS

A retrospective cohort study was undertaken at a tertiary-referral pediatric gender service. Subjects were included if they'd received a testicular biopsy in association with the commencement of GAT between 2010 and 2019. The primary outcome measure was successful sperm retrieval, and potential predictors included age, testicular volume and serum testosterone, LH and FSH levels.

RESULTS

Of 25 subjects who received a biopsy prior to starting any GAT, 17 had successful sperm retrieval. While age, testosterone, LH and FSH levels showed minimal differences, testicular volume was significantly higher in those with successful sperm retrieval, and a threshold of ≥ 10 mL showed 92% sensitivity and 71% specificity in predicting successful retrieval. An additional 6 patients received a biopsy after starting puberty suppression and before commencement of oestrogen, and one of these individuals had sperm successfully retrieved despite > 2 years of regular puberty suppression.

CONCLUSION

These findings suggest that testicular volume is most useful in predicting successful sperm retrieval following testicular biopsy in transgender adolescents and are likely to be of relevance to other young people undertaking FP, including those with cancer.

Recent advances: fertility preservation and fertility restoration options for males and females

Fertility preservation is the process of saving gametes, embryos, gonadal tissues and/or gonadal cells for individuals who are at risk of infertility due to disease, medical treatments, age, genetics, or other circumstances. Adult patients have the options to preserve eggs, sperm, or embryos that can be used in the future to produce biologically related offspring with assisted reproductive technologies. These options are not available to all adults or to children who are not yet producing mature eggs or sperm. Gonadal cells/tissues have been frozen for several thousands of those patients worldwide with anticipation that new reproductive technologies will be available in the future. Therefore, the fertility preservation medical and research communities are obligated to responsibly develop next-generation reproductive technologies and translate them into clinical practice. We briefly describe standard options to preserve and restore fertility, but the emphasis of this review is on experimental options, including an assessment of readiness for translation to the human fertility clinic.

Long-term follow-up of boys who have undergone a testicular biopsy for fertility preservation

STUDY QUESTION

What is the long-term reproductive health outcome of patients who have undergone testicular sampling for fertility preservation (FP) before and during the pubertal transition period?

SUMMARY ANSWER

In long-term follow-up after testicular sampling for FP, hormonal data showed that 33% of patients had primary seminiferous tubule insufficiency (high FSH) while semen analyses showed 52% of patients having a severe reduction in total sperm counts or complete absence of ejaculated sperm.

WHAT IS KNOWN ALREADY

During childhood and adolescence, both treatments for cancer and benign haematological diseases that require a bone marrow transplantation, can be detrimental to spermatogenesis by depleting the spermatogonial stem cell population. A testicular biopsy prior to chemotherapy or radiotherapy, even though still an experimental procedure, is now recommended for FP by European and USA oncofertility societies if performed within an institutional research setting. While short-term follow-up studies showed little to no post-operative complications and a normal testicular development after 1 year, data regarding the long-term follow-up of boys who have undergone this procedure are still lacking.

STUDY DESIGN, SIZE, DURATION

This is a longitudinal retrospective cohort study that reports on the long-term follow-up of pre- and peri-pubertal boys who have undergone a testicular biopsy for FP between May 2005 and May 2020. All the patients included in this study were referred to our programme by haematologists-oncologists who are part of a regional multi-centric collaborative care pathway.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Of the 151 boys referred to our FP programme, 139 parents/legal guardians accepted that their child undergo a testicular biopsy. Patient characteristics (i.e. age at biopsy, urogenital history, pubertal status at diagnosis), indications (disease type and dosage of gonadotoxic treatments), operative and post-operative data (biopsy volume, surgical complications), anatomopathological analyses (presence/absence of spermatogonia, Johnsen score) and reproductive data (semen analyses, FSH, LH, testosterone levels) were collected from the institutions' FP database and medical records or from the 'Brussels Health Network'. Cumulative alkylating agent treatment was quantified using the cyclophosphamide equivalent dose (CED). Patients who were 14 years or older at the time of the follow-up and in whom the testicular tissue was shown to contain spermatogonia were included in the reproductive outcome analysis. Comparison of the sperm count findings (absence/presence of spermatozoa) and FSH levels (high (≥10 IU/l)/normal) between patients who were either pre- (Tanner 1) or peri-pubertal (Tanner >1) at the time of the biopsy was done using the Mann-Whitney U or Fisher's tests. A multiple logistic regression was used to study the relationship between the hormone reproductive outcome (high versus normal FSH), as a proxy marker for fertility, and both the pubertal status (Tanner 1 versus Tanner >1) and Johnsen score at the time of the biopsy, while adjusting for CED.

MAIN RESULTS AND THE ROLE OF CHANCE

A testicular biopsy was performed in 139 patients either before (129/139) or after (10/139) the start of a gonadotoxic treatment. Post-operative complications occurred in 2.1% (3/139). At the time of the procedure, 88% (122/139) of patients were pre-pubertal and 12% (17/139) were peri-pubertal. The presence of spermatogonia was documented in 92% (128/139) of cases. Follow-up data were available for 114 patients after excluding 23 deceased and two patients lost to follow-up. A paediatric endocrinologist's follow-up including clinical examination and data on reproductive hormones was available for 57 patients (age ≥14) and 19 (33%) of these were found to have high FSH levels (20 ± 8.8 IU/l). There were 37 patients who had returned to the reproductive specialist's consultation for post-treatment fertility counselling and results on semen analysis were available in 27 of these cases; 14/27 (52%) had severely impaired semen parameters including 8 who were azoospermic. Among patients who received an alkylating agent-based treatment (n = 42), a peri-pubertal status (Tanner >1) at the time of diagnosis/biopsy was found to be associated with a higher risk of having primary testicular failure (defined by an FSH ≥ 10 IU/l) after treatment completion with an OR of 6.4 (95% CI 1.22-33.9; P = 0.03). Of all the patients, 2.6% had already fulfilled their wish to build a family or were actively seeking parenthood.

LIMITATIONS, REASONS FOR CAUTION

Although this is the largest cohort with follow-up data providing proxy markers of the reproductive potential of boys in whom a testicular biopsy for FP was performed before puberty or during the pubertal transition period, the amount of data provided is limited, and originating from a single programme. Further data collection to confirm the observations in other settings is therefore awaited.

WIDER IMPLICATIONS OF THE FINDINGS

Testicular sampling for FP should be offered to boys at risk of losing their fertility (and is recommended for those at high risk) as part of ethically approved research programmes. Long-term follow-up data on increasing numbers of boys who have undergone an FP procedure will help improve patient care in the future as patient-specific factors (e.g. urogenital history, age at gonadotoxic therapy) appear to influence their reproductive potential after gonadotoxic therapies.

STUDY FUNDING/COMPETING INTEREST(S)

FNRS-Télévie, the Salus Sanguinis Foundation and the Belgian Foundation against Cancer supported the studies required to launch the FP programme. The authors declare that they have no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Fertility preservation for male patients with childhood, adolescent, and young adult cancer: recommendations from the PanCareLIFE Consortium and the International Late Effects of Childhood Cancer Guideline Harmonization Group

Male patients with childhood, adolescent, and young adult cancer are at an increased risk for infertility if their treatment adversely affects reproductive organ function. Future fertility is a primary concern of patients and their families. Variations in clinical practice are barriers to the timely implementation of interventions that preserve fertility. As part of the PanCareLIFE Consortium, in collaboration with the International Late Effects of Childhood Cancer Guideline Harmonization Group, we reviewed the current literature and developed a clinical practice guideline for fertility preservation in male patients who are diagnosed with childhood, adolescent, and young adult cancer at age 25 years or younger, including guidance on risk assessment and available methods for fertility preservation. The Grading of Recommendations Assessment, Development and Evaluation methodology was used to grade the available evidence and to form the recommendations. Recognising the need for global consensus, this clinical practice guideline used existing evidence and international expertise to rigorously develop transparent recommendations that are easy to use to facilitate the care of male patients with childhood, adolescent, and young adult cancer who are at high risk of fertility impairment and to enhance their quality of life.

Installing oncofertility programs for common cancers in optimum resource settings (Repro-Can-OPEN Study Part II): a committee opinion

PURPOSE

The main objective of Repro-Can-OPEN Study Part 2 is to learn more about oncofertility practices in optimum resource settings to provide a roadmap to establish oncofertility best practice models.

METHODS

As an extrapolation for oncofertility best practice models in optimum resource settings, we surveyed 25 leading and well-resourced oncofertility centers and institutions from the USA, Europe, Australia, and Japan. The survey included questions on the availability and degree of utilization of fertility preservation options in case of childhood cancer, breast cancer, and blood cancer.

RESULTS

All surveyed centers responded to all questions. Responses and their calculated oncofertility scores showed three major characteristics of oncofertility practice in optimum resource settings: (1) strong utilization of sperm freezing, egg freezing, embryo freezing, ovarian tissue freezing, gonadal shielding, and fractionation of chemo- and radiotherapy; (2) promising utilization of GnRH analogs, oophoropexy, testicular tissue freezing, and oocyte in vitro maturation (IVM); and (3) rare utilization of neoadjuvant cytoprotective pharmacotherapy, artificial ovary, in vitro spermatogenesis, and stem cell reproductive technology as they are still in preclinical or early clinical research settings. Proper technical and ethical concerns should be considered when offering advanced and experimental oncofertility options to patients.

CONCLUSIONS

Our Repro-Can-OPEN Study Part 2 proposed installing specific oncofertility programs for common cancers in optimum resource settings as an extrapolation for best practice models. This will provide efficient oncofertility edification and modeling to oncofertility teams and related healthcare providers around the globe and help them offer the best care possible to their patients.

Fertility preservation for prepubertal boys: lessons learned from the past and update on remaining challenges towards clinical translation

BACKGROUND

Childhood cancer incidence and survivorship are both on the rise. However, many lifesaving treatments threaten the prepubertal testis. Cryopreservation of immature testicular tissue (ITT), containing spermatogonial stem cells (SSCs), as a fertility preservation (FP) option for this population is increasingly proposed worldwide. Recent achievements notably the birth of non-human primate (NHP) progeny using sperm developed in frozen-thawed ITT autografts has given proof of principle of the reproductive potential of banked ITT. Outlining the current state of the art on FP for prepubertal boys is crucial as some of the boys who have cryopreserved ITT since the early 2000s are now in their reproductive age and are already seeking answers with regards to their fertility.

OBJECTIVE AND RATIONALE

In the light of past decade achievements and observations, this review aims to provide insight into relevant questions for clinicians involved in FP programmes. Have the indications for FP for prepubertal boys changed over time? What is key for patient counselling and ITT sampling based on the latest achievements in animals and research performed with human ITT? How far are we from clinical application of methods to restore reproductive capacity with cryostored ITT?

SEARCH METHODS

An extensive search for articles published in English or French since January 2010 to June 2020 using keywords relevant to the topic of FP for prepubertal boys was made in the MEDLINE database through PubMed. Original articles on fertility preservation with emphasis on those involving prepubertal testicular tissue, as well as comprehensive and systematic reviews were included. Papers with redundancy of information or with an absence of a relevant link for future clinical application were excluded. Papers on alternative sources of stem cells besides SSCs were excluded.

OUTCOMES

Preliminary follow-up data indicate that around 27% of boys who have undergone testicular sampling as an FP measure have proved azoospermic and must therefore solely rely on their cryostored ITT to ensure biologic parenthood. Auto-transplantation of ITT appears to be the first technique that could enter pilot clinical trials but should be restricted to tissue free of malignant cells. While in vitro spermatogenesis circumvents the risk linked to cancer cell contamination and has led to offspring in mice, complete spermatogenesis has not been achieved with human ITT. However, generation of haploid germ cells paves the way to further studies aimed at completing the final maturation of germ cells and increasing the efficiency of the processes.

WIDER IMPLICATIONS

Despite all the research done to date, FP for prepubertal boys remains a relatively young field and is often challenging to healthcare providers, patients and parents. As cryopreservation of ITT is now likely to expand further, it is important not only to acknowledge some of the research questions raised on the topic, e.g. the epigenetic and genetic integrity of gametes derived from strategies to restore fertility with banked ITT but also to provide healthcare professionals worldwide with updated knowledge to launch proper multicollaborative care pathways in the field and address clinical issues that will come-up when aiming for the child's best interest.

Fertility education for adolescent cancer patients: Gaps in current clinical practice in Europe

OBJECTIVE

As adolescent cancer patients may suffer from infertility following treatment, fertility counselling is essential. Our aim was to explore the current situation in four European countries in terms of (I) education about the risk for infertility, (II) counselling on fertility preservation, (III) patients' knowledge on fertility, (IV) sufficiency of information and (V) uptake of cryopreservation.

METHODS

In total, 113 patients (13-20 years) at 11 study centres completed a self-report questionnaire three and six months after cancer diagnosis. Multivariate logistic regression was used to estimate odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

As many as 80.2% of participants reported having received education about the risk for infertility prior to treatment, 73.2% recalled counselling on fertility preservation. Only 52.3% stated they felt sufficiently informed to make a decision. Inability to recall counselling on fertility preservation (OR = 0.03, CI: 0.00-0.47) and female gender (OR = 0.11, CI: 0.03-0.48) was associated with lower use of cryopreservation, whereas older age was associated with higher use.

CONCLUSION

Fertility counselling was available to a relatively high proportion of patients, and it did influence the utilisation of cryopreservation. However, many patients did not feel sufficiently informed. Further improvement is needed to enable adolescent cancer patients to make an informed decision on fertility preservation.

Fertility preservation in boys: recent developments and new insights †

BACKGROUND

Infertility is an important side effect of treatments used for cancer and other non-malignant conditions in males. This may be due to the loss of spermatogonial stem cells (SSCs) and/or altered functionality of testicular somatic cells (e.g. Sertoli cells, Leydig cells). Whereas sperm cryopreservation is the first-line procedure to preserve fertility in post-pubertal males, this option does not exist for prepubertal boys. For patients unable to produce sperm and at high risk of losing their fertility, testicular tissue freezing is now proposed as an alternative experimental option to safeguard their fertility.

OBJECTIVE AND RATIONALE

With this review, we aim to provide an update on clinical practices and experimental methods, as well as to describe patient management inclusion strategies used to preserve and restore the fertility of prepubertal boys at high risk of fertility loss.

SEARCH METHODS

Based on the expertise of the participating centres and a literature search of the progress in clinical practices, patient management strategies and experimental methods used to preserve and restore the fertility of prepubertal boys at high risk of fertility loss were identified. In addition, a survey was conducted amongst European and North American centres/networks that have published papers on their testicular tissue banking activity.

OUTCOMES

Since the first publication on murine SSC transplantation in 1994, remarkable progress has been made towards clinical application: cryopreservation protocols for testicular tissue have been developed in animal models and are now offered to patients in clinics as a still experimental procedure. Transplantation methods have been adapted for human testis, and the efficiency and safety of the technique are being evaluated in mouse and primate models. However, important practical, medical and ethical issues must be resolved before fertility restoration can be applied in the clinic.Since the previous survey conducted in 2012, the implementation of testicular tissue cryopreservation as a means to preserve the fertility of prepubertal boys has increased. Data have been collected from 24 co-ordinating centres worldwide, which are actively offering testis tissue cryobanking to safeguard the future fertility of boys. More than 1033 young patients (age range 3 months to 18 years) have already undergone testicular tissue retrieval and storage for fertility preservation.

LIMITATIONS REASONS FOR CAUTION

The review does not include the data of all reproductive centres worldwide. Other centres might be offering testicular tissue cryopreservation. Therefore, the numbers might be not representative for the entire field in reproductive medicine and biology worldwide. The key ethical issue regarding fertility preservation in prepubertal boys remains the experimental nature of the intervention.

WIDER IMPLICATIONS

The revised procedures can be implemented by the multi-disciplinary teams offering and/or developing treatment strategies to preserve the fertility of prepubertal boys who have a high risk of fertility loss.

STUDY FUNDING/COMPETING INTERESTS

The work was funded by ESHRE. None of the authors has a conflict of interest.

Progress in translational reproductive science: testicular tissue transplantation and in vitro spermatogenesis

Since the birth of the first child conceived via in vitro fertilization 40 years ago, fertility treatments and assisted reproductive technology have allowed many couples to reach their reproductive goals. As of yet, no fertility options are available for men who cannot produce functional sperm, but many experimental therapies have demonstrated promising results in animal models. Both autologous (stem cell transplantation, de novo morphogenesis, and testicular tissue grafting) and outside-the-body (xenografting and in vitro spermatogenesis) approaches exist for restoring sperm production in infertile animals with varying degrees of success. Once safety profiles are established and an ideal patient population is chosen, some of these techniques may be ready for human experimentation in the near future, with likely clinical implementation within the next decade.

Setting Up a Cryopreservation Programme for Immature Testicular Tissue: Lessons Learned After More Than 15 Years of Experience

Young boys undergoing gonadotoxic treatments are at high risk of spermatogonial stem cell (SSC) loss and fertility problems later in life. Stem cell loss can also occur in specific genetic conditions, eg, Klinefelter syndrome (KS). Before puberty, these boys do not yet produce sperm. Hence, they cannot benefit from sperm banking. An emerging alternative is the freezing of testicular tissue aiming to preserve the SSCs for eventual autologous transplantation or in vitro maturation at adult age. Many fertility preservation programmes include cryopreservation of immature testicular tissue, although the restoration procedures are still under development. Until the end of 2018, the Universitair Ziekenhuis Brussel has frozen testicular tissues of 112 patients between 8 months and 18 years of age. Testicular tissue was removed in view of gonadotoxic cancer treatment (35%), gonadotoxic conditioning therapy for bone marrow transplantation (35%) or in boys diagnosed with KS (30%). So far, none of these boys had their testicular tissue transplanted back. This article summarizes our experience with cryopreservation of immature testicular tissue over the past 16 years (2002-2018) and describes the key issues for setting up a cryopreservation programme for immature testicular tissue as a means to safeguard the future fertility of boys at high risk of SSC loss.

Fertility preservation in oncology patients: A literature review examining current fertility preservation techniques and access to oncofertility services in Australia

BACKGROUND

In Australia, between the years 2010 and 2014, over 4500 adolescents and young adults (15-25 years old) were diagnosed with cancer. Treatment regimens are often gonadotoxic and are well known to induce ovarian and testicular failure. Oncofertility is an emerging discipline in obstetrics and gynaecology which seeks to preserve and restore the reproductive future of cancer patients.

AIM

To perform a systematic literature review to assess the current fertility preservation techniques available to patients and examine access and uptake of fertility preservation in Australia.

MATERIALS AND METHODS

Electronic databases, including Medline, Cochrane Review, SCOPUS and CINHAL, were searched for peer-reviewed publications and national guidelines examining oncofertility practices from 2008 to July 2018. Three hundred and seventy-five articles were initially screened, with 158 articles for full text review and an additional five clinical guidelines were identified.

RESULTS

There is a paucity of Australian data on oncofertility with <50% of data included for analysis reflecting the Australian experience. The majority of primary research included retrospective papers with small cohort numbers. Key areas addressed included live birth outcomes, uptake of services and patient and physician perspectives on fertility preservation. Few articles sought to examine the positive and negative side effects of fertility preservation in oncology, social challenges of oncofertility and access to services worldwide.

CONCLUSION

Oncofertility is an emerging discipline which seeks to provide safe, efficient and effective fertility preservation options for young adults and adolescents diagnosed with cancer. A multi-disciplinary approach with collaborative communication with oncologists is key to providing this service within Australia.

Fertility Preservation in Male to Female Transgender Patients

Gender dysphoria, or the incongruence between gender identification and sex assigned at birth with associated discomfort or distress, manifests in transgender patients, whose multifaceted care includes puberty suppression, cross-sex hormonal therapy, and gender-affirming surgery. Discussion of fertility preservation (FP) is paramount because many treatments compromise future fertility, and although transgender patients demonstrate desire for children, use of FP remains low for a plethora of reasons. In transgender women, established FP options include ejaculated sperm cryopreservation, electroejaculation, or testicular sperm extraction. Further research is needed regarding reproductive health and FP in transgender patients.

Testicular tissue cryopreservation: 8 years of experience from a coordinated network of academic centers

STUDY QUESTION

Is it feasible to disseminate testicular tissue cryopreservation with a standardized protocol through a coordinated network of centers and provide centralized processing/freezing for centers that do not have those capabilities?

SUMMARY ANSWER

Centralized processing and freezing of testicular tissue from multiple sites is feasible and accelerates recruitment, providing the statistical power to make inferences that may inform fertility preservation practice.

WHAT IS KNOWN ALREADY

Several centers in the USA and abroad are preserving testicular biopsies for patients who cannot preserve sperm in anticipation that cell- or tissue-based therapies can be used in the future to generate sperm and offspring.

STUDY DESIGN, SIZE, DURATION

Testicular tissue samples from 189 patients were cryopreserved between January 2011 and November 2018. Medical diagnosis, previous chemotherapy exposure, tissue weight, and presence of germ cells were recorded.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human testicular tissue samples were obtained from patients undergoing treatments likely to cause infertility. Twenty five percent of the patient's tissue was donated to research and 75% was stored for patient's future use. The tissue was weighed, and research tissue was fixed for histological analysis with Periodic acid-Schiff hematoxylin staining and/or immunofluorescence staining for DEAD-box helicase 4, and/or undifferentiated embryonic cell transcription factor 1.

MAIN RESULTS AND THE ROLE OF CHANCE

The average age of fertility preservation patients was 7.9 (SD = 5) years and ranged from 5 months to 34 years. The average amount of tissue collected was 411.3 (SD = 837.3) mg and ranged from 14.4 mg-6880.2 mg. Malignancies (n = 118) were the most common indication for testicular tissue freezing, followed by blood disorders (n = 45) and other conditions (n = 26). Thirty nine percent (n = 74) of patients had initiated their chemotherapy prior to undergoing testicular biopsy. Of the 189 patients recruited to date, 137 have been analyzed for the presence of germ cells and germ cells were confirmed in 132.

LIMITATIONS, REASONS FOR CAUTION

This is a descriptive study of testicular tissues obtained from patients who were at risk of infertility. The function of spermatogonia in those biopsies could not be tested by transplantation due limited sample size.

WIDER IMPLICATIONS OF THE FINDINGS

Patients and/or guardians are willing to pursue an experimental fertility preservation procedure when no alternatives are available. Our coordinated network of centers found that many patients request fertility preservation after initiating gonadotoxic therapies. This study demonstrates that undifferentiated stem and progenitor spermatogonia may be recovered from the testicular tissues of patients who are in the early stages of their treatment and have not yet received an ablative dose of therapy. The function of those spermatogonia was not tested.

STUDY FUNDING/COMPETING INTEREST(S)

Support for the research was from the Eunice Kennedy Shriver National Institute for Child Health and Human Development grants HD061289 and HD092084, the Scaife Foundation, the Richard King Mellon Foundation, the Departments of Ob/Gyn & Reproductive Sciences and Urology of the University of Pittsburgh Medical Center, United States-Israel Binational Science Foundation (BSF), and the Kahn Foundation. The authors declare that they do not have competing financial interests.

Development of a Pediatric Fertility Preservation Program: A Report From the Pediatric Initiative Network of the Oncofertility Consortium

Infertility is known to decrease quality of life among adults. In some cases, infertility is caused by medical conditions and/or treatments prescribed in childhood, and using methods to protect or preserve fertility may expand future reproductive possibilities. Structured programs to offer counseling about infertility risk and fertility preservation options are essential in the care of pediatric patients facing fertility-threatening conditions or treatments, yet multiple barriers to program development exist. This report was developed from the institutional experiences of members of the Pediatric Initiative Network of the Oncofertility Consortium, with the intent of providing guidance for health care providers aiming to establish programs at institutions lacking pediatric fertility preservation services. The mechanics of building a fertility preservation program are discussed, including essential team members, target populations, fertility preservation options (both established and experimental), survivorship issues, research opportunities, and ethical considerations. Common barriers to program development and utilization, including low referral rates and financial concerns, are also discussed, and recommendations made for overcoming such barriers.

Oncofertility-An emerging discipline rather than a special consideration

Originally absent from the oncologist's consult, then placed in a 'quality of life' rubric, oncofertility should now be an essential part of a comprehensive cancer treatment plan in patients of reproductive age, including adolescents and young adults (AYAs). Oncofertility encompasses the endocrine health of the patient, as well as fertility management options. Thus, pubertal transitions in males and females, bone health, and menstrual health are all part of this discipline, enabling practitioners to work in interdisciplinary teams to solve problems in reproductive health. This review provides a summary of the essential considerations required for the assessement of reproductive risk and choice of fertility preservation options as well as considerations for developing oncofertility services for AYAs.

Cryopreservation of testicular tissue in pre-pubertal and adolescent boys at risk for infertility: A low risk procedure

INTRODUCTION

Cryopreservation of testicular tissue (TT) has become an increasingly attractive option for fertility preservation (FP), particularly for pre-pubertal boys at risk for gonadotoxicity from cancer therapy. At our institution, all at-risk families undergo counseling regarding infertility risk and available FP strategies, including this vulnerable patient population. As the technology required to use the acquired tissue is, as yet, unproven, it is paramount to document minimal morbidity and complications from this procedure. Herein, we report these outcomes for all pre-pubertal patients who have undergone TT biopsies for FP.

METHODS

We retrospectively reviewed consecutive patients who underwent unilateral open TT biopsies between January 2014 and December 2016. Patient diagnosis, age, concomitant procedures, anesthetic type, complications, procedure times, planned therapy, and bleeding were evaluated.

RESULTS

Of a total of 34 patients, mean age at biopsy was 6.9 ± 4.4years. Diagnoses included: leukemia/lymphoma (n = 12), solid tumors (n = 15) and non-neoplastic disorders (hemophagocytic lymphohistiocytosis, aplastic anemia; n = 7). Twenty-two patients (64.7%) were scheduled for stem cell transplantation. Eleven (32.4%) patients had not received any chemotherapy prior to TT biopsy, while all others had exposure preceding the biopsy. Biopsies were performed in conjunction with other procedures (central line placement, bone marrow biopsy, lumbar puncture, lymph node biopsy) in 29 cases (85.3%), with stand-alone procedures performed in the remainder (n = 5). In stand-alone cases, mean anesthetic time was 22 ± 8.7 min. Overall, two (5.9%) patients had complications after biopsy: 1) ipsilateral epididymo-orchitis (resolved with antibiotics) and 2) ipsilateral torsed appendix testis (managed conservatively) (Table).

CONCLUSION

In this series, pre-pubertal TT biopsy for cryopreservation was safely performed, and was most often coordinated concomitantly with other medically necessary procedures. The safety profile reported herein supports performing this procedure while technological advances fulfill the requirements to make it a viable option for future fertility.