Multiple approaches for individualized fertility protective therapy in cancer patients

The Usage of Cryopreserved Reproductive Material in Cancer Patients Undergoing Fertility Preservation Procedures

BACKGROUND

Many cancer treatment methods can affect fertility by damaging the reproductive organs and glands that control fertility. Changes can be temporary or permanent. In order to preserve the fertility of cancer patients and protect the genital organs against gonadotoxicity, methods of fertility preservation are increasingly used. Considering that some patients ultimately decide not to use cryopreserved reproductive material, this review analysed the percentage of post-cancer patients using cryopreserved reproductive material, collected before treatment as part of fertility preservation.

METHODS

A systematic search of studies was carried out in accordance with the Cochrane Collaboration guidelines, based on a previously prepared research protocol. The search was conducted in Medline (via PubMed), Embase (via OVID), and the Cochrane Library. In addition, a manual search was performed for recommendations/clinical practice guidelines regarding fertility preservation in cancer patients.

RESULTS

Twenty-six studies met the inclusion criteria. The studies included in the review discussed the results of cryopreservation of oocytes, embryos, ovarian tissue, and semen. In 10 studies, the usage rate of cryopreserved semen ranged from 2.6% to 21.5%. In the case of cryopreserved female reproductive material, the return/usage rate ranged from 3.1% to 8.7% for oocytes, approx. 9% to 22.4% for embryos, and 6.9% to 30.3% for ovarian tissue. In studies analysing patients' decisions about unused reproductive material, continuation of material storage was most often indicated. Recovering fertility or death of the patient were the main reasons for rejecting cryopreserved semen in the case of men.

CONCLUSION

Fertility preservation before gonadotoxic treatment is widely recommended and increasingly used in cancer patients. The usage rate is an important indicator for monitoring the efficacy of these methods. In all of the methods described in the literature, this indicator did not exceed 31%. It is necessary to create legal and organizational solutions regulating material collection and storage and to create clear paths for its usage in the future, including by other recipients.

Pharmacological inhibition of the PI3K/PTEN/Akt and mTOR signalling pathways limits follicle activation induced by ovarian cryopreservation and in vitro culture

BACKGROUND

Cryopreservation and transplantation of ovarian tissue (OTCTP) represent a promising fertility preservation technique for prepubertal patients or for patients requiring urgent oncological management. However, a major obstacle of this technique is follicle loss due to, among others, accelerated recruitment of primordial follicles during the transplantation process, leading to follicular reserve loss in the graft and thereby potentially reducing its lifespan. This study aimed to assess how cryopreservation itself impacts follicle activation.

RESULTS

Western blot analysis of the PI3K/PTEN/Akt and mTOR signalling pathways showed that they were activated in mature or juvenile slow-frozen murine ovaries compared to control fresh ovaries. The use of pharmacological inhibitors of follicle signalling pathways during the cryopreservation process decreased cryopreservation-induced follicle recruitment. The second aim of this study was to use in vitro organotypic culture of cryopreserved ovaries and to test pharmacological inhibitors of the PI3K/PTEN/Akt and mTOR pathways. In vitro organotypic culture-induced activation of the PI3K/PTEN/Akt pathway is counteracted by cryopreservation with rapamycin and in vitro culture in the presence of LY294002. These results were confirmed by follicle density quantifications. Indeed, follicle development is affected by in vitro organotypic culture, and PI3K/PTEN/Akt and mTOR pharmacological inhibitors preserve primordial follicle reserve.

CONCLUSIONS

Our findings support the hypothesis that inhibitors of mTOR and PI3K might be an attractive tool to delay primordial follicle activation induced by cryopreservation and culture, thus preserving the ovarian reserve while retaining follicles in a functionally integrated state.

Breast Cancer Survivorship, Quality of Life, and Late Toxicities

Breast cancer is the most frequent cancer in women: in 2018, almost two million cases have been diagnosed all over the world and it represents the principal cause of death from a neoplastic disease in women. In the past years, breast cancer prognosis has significantly improved over time: currently 5-year survival rates are in the range of 90%, and 10-year survival is about 80%. This improvement has been mostly observed in western countries, due to high coverage and compliance with screening programs, leading to early diagnosis, i.e., when the disease is at a subclinical level, and to an improvement in tumor molecular characterization and innovative systemic treatments. Yet the identification of different biological breast cancer subtypes prompted the development of innovative targeted agents and improved treatment personalization. On the other hand, longer survival rates and increasing proportions of cured patients require dedicated strategies to manage long-term sequelae of breast cancer treatments, with particular attention to quality of life. This review analyzes the most important issues, potentially occurring with cancer treatments, concerning long-term sequelae and quality of life, to define a global approach to breast cancer survivorship.

Slow Freezing Versus Vitrification of Mouse Ovaries: from Ex Vivo Analyses to Successful Pregnancies after Auto-Transplantation

Slow freezing (SF) is the reference method for ovarian tissue cryopreservation. Vitrification (VT) constitutes an alternative but controversial method. This study compares SF and VT (open [VTo] and closed [VTc] systems) in terms of freezing damage and fertility restoration ability. In vitro analyses of C57Bl/6 SF or VTo-ovaries, immediately after thawing/warming or after culture (cult), revealed that event though follicular density was similar between all groups, nuclear density was decreased in VTo-ovaries compared to CT-ovaries (CT = 0.50 ± 0.012, SF = 0.41 ± 0.03 and VTo = 0.29 ± 0.044, p < 0.01). Apoptosis was higher in VTo-cult ovaries compared to SF-cult ovaries (p < 0.001) whereas follicular Bmp15 and Amh gene expression levels were decreased in the ovaries after culture, mostly after VTo (p < 0.001). Natural mating after auto-transplantation of SF, VTo and VTc-ovaries revealed that most mice recovered their oestrous cycle. Fertility was only restored with SF and VTo ovaries (SF: 68%; VTo: 63%; VTc: 0%; p < 0.001). Mice auto-transplanted with SF and VTo-ovaries achieved the highest number of pregnancies. In conclusion, in vitro, no differences between SF and VTo were evident immediately after thawing/warming but VTo ovaries displayed alterations in apoptosis and follicular specific proteins after culture. In vivo, SF and VTo ovary auto-transplantation fully restored fertility whereas with VTc-ovary auto-transplantation no pregnancies were achieved.

Anti-Mullerian Hormone: Above and Beyond Conventional Ovarian Reserve Markers

Management of ovarian dysfunctions requires accurate estimation of ovarian reserve (OR). Therefore, reproductive hormones and antral follicle count (AFC) are assessed to indicate OR. Serum anti-Mullerian hormone (AMH) is a unique biomarker that has a critical role in folliculogenesis as well as steroidogenesis within ovaries. Secretion from preantral and early antral follicles renders AMH as the earliest marker to show OR decline. In this review we discuss the dynamics of circulating AMH that remarkably vary with sex and age. As it emerges as a marker of gonadal development and reproductive disorders, here we summarize the role of AMH in female reproductive physiology and provide evidence of higher accuracy in predicting ovarian response to stimulation. Further, we attempt to compile potential clinical applications in children and adults. We propose that AMH evaluation has a potential role in effectively monitoring chemotherapy and pelvic radiation induced ovarian toxicity. Furthermore, AMH guided ovarian stimulation can lead to individualization of therapeutic strategies for infertility treatment. However future research on AMH levels within follicular fluid may pave the way to establish it as a marker of "quality" besides "quantity" of the growing follicles.

Folliculogenesis Is Not Fully Inhibited during GnRH Analogues Treatment in Mice Challenging Their Efficiency to Preserve the Ovarian Reserve during Chemotherapy in This Model

As many chemotherapy regimens induce follicular depletion, fertility preservation became a major concern in young cancer patients. By maintaining follicles at the resting stage, gonadotropin-releasing hormone analogues (GnRHa) were proposed as an ovarian-protective option during chemotherapy. However, their efficacy and mechanisms of action remain to be elucidated. Mice were dosed with cyclophosphamide (Cy, 100–500mg/kg i.p) to quantify follicular depletion and evaluate apoptosis at different times. We observed a dose-dependent depletion of the follicular reserve within 24 hours after Cy injection with a mean follicular loss of 45% at the dose of 200mg/kg. Apoptosis occurs in the granulosa cells of growing follicles within 12 hours after Cy treatment, while no apoptosis was detected in resting follicles suggesting that chemotherapy acutely affects both resting and growing follicles through different mechanisms. We further tested the ability of both GnRH agonist and antagonist to inhibit oestrus cycles, follicular growth and FSH secretion in mice and to protect ovarian reserve against chemotherapy. Although GnRHa were efficient to disrupt oestrus cycles, they failed to inhibit follicular development, irrespective of the doses and injection sites (sc or im). Around 20% of healthy growing follicles were still observed during GnRHa treatment and serum FSH levels were not reduced either by antagonist or agonist. GnRHa had no effect on Cy-induced follicular damages. Thus, we showed that GnRHa were not as efficient at inhibiting the pituitary-gonadal axis in mice as in human. Furthermore, the acute depletion of primordial follicles observed after chemotherapy does not support the hypothesis that the ovary may be protected by gonadotropin suppression.

IVF for fertility preservation in breast cancer patients--efficacy and safety issues

BACKGROUND

Potential risks on future fertility have become a dominant issue in consultation and management of newly diagnosed young cancer patients. Several fertility preservation strategies are currently available. Of those, ovarian stimulation followed by IVF and embryo cryopreservation is the most established one and is especially applicable in reproductive aged breast cancer patients.

AIM

The aim of this study is to provide a comprehensive review on ovarian stimulation and IVF for fertility preservation in newly diagnosed breast cancer patients.

METHODS

Review of relevant literature is available through PubMed and Google scholar.

RESULTS

The use of IVF for fertility preservation in breast cancer patients raises dilemmas regarding efficacy and safety of controlled ovarian stimulation. Among these are the suggested role of malignancy and BRCA mutation in reducing ovarian response to stimulation, strategies designated to protect against hyper-estrogenic state associated with stimulation (co-treatment with tamoxifen or letrozole), and possible adjustments to accommodate oncologic-related time constraints.

CONCLUSION

Ovarian stimulation followed by IVF forms an important fertility preservation strategy for newly diagnosed young breast cancer patients, though live born rates following thawed embryo transfer in these patients are still lacking. Recent advances in controlled ovarian stimulation protocols provide practical options for some of the challenges that breast cancer patients present.

Progesterone levels in letrozole associated controlled ovarian stimulation for fertility preservation in breast cancer patients

STUDY QUESTION

Are progesterone levels after letrozole-associated controlled ovarian stimulation (COS) for fertility preservation in breast cancer patients, lower than after standard in vitro fertilization (IVF) cycles?

SUMMARY ANSWER

During the luteal phase of letrozole-associated COS cycles (triggered with human chorionic gonadotrophin (hCG)) progesterone levels are similarly elevated to those obtained after standard COS without letrozole.

WHAT IS KNOWN ALREADY

Current fertility preservation strategies for breast cancer patients include association of COS with the aromatase inhibitor letrozole to harvest several mature oocytes while maintaining low estradiol levels. Data on progesterone levels are however lacking despite growing evidence of the role of progesterone in breast tumorigenesis.

STUDY DESIGN, SIZE, DURATION

This is a prospective observational study comparing estradiol and progesterone levels of 21 breast cancer patients undergoing letrozole-associated COS with 21 infertile patients undergoing standard COS for IVF and/or intra cytoplasmic sperm injection (ICSI).

PARTICIPANTS/MATERIALS, SETTING, METHODS

All patients underwent COS with a GnRH antagonist protocol. In the fertility preservation group, ovulation induction was started in the follicular or luteal phase depending on the chemotherapy schedule and in 10 cases a GnRH antagonist was administered during luteal phase to induce luteolysis. Final oocyte maturation was induced by hCG in all patients. Estradiol and progesterone levels were measured on the day of hCG, at oocyte retrieval, and on days 3 and 8 after oocyte retrieval. Hormone levels in fertility preservation patients were compared with those observed in infertility patients.

MAIN RESULTS AND THE ROLE OF CHANCE

While estradiol levels were significantly lower in the fertility preservation group compared with the control group (P < 0.001), progesterone levels were similar at all times, including patients receiving a GnRH antagonist during the luteal phase.

LIMITATIONS, REASONS FOR CAUTION

The studied populations (breast cancer and infertile patients) are different, which may induce selection bias. The small sample size limits the study's statistical power and the possibility to perform multivariate analysis. Recruitment of the study and control patients was completed at the same time; however, enrollment of controls started at a later time.

WIDER IMPLICATIONS OF THE FINDINGS

While the use of letrozole in fertility preservation patients has a favorable effect on estrogen levels, no benefit is seen for progesterone levels which are high and comparable with progesterone levels after standard COS in IVF patients. As progesterone has been associated with tumor cell proliferation, caution is mandatory. Modified protocols including GnRH agonist triggering should be investigated.

In vivo fate mapping of cryopreserved murine ovarian grafts

Background

Cryopreservation of ovarian tissue has been suggested as an alternative to restore fertility for ovarian failure before chemotherapy.

Methods

Ovaries of donor FVB/N-Tg (PolII–Luc) Ltc transgenic mice (n = 5) were cryopreserved and transplanted to the back muscles of recipient FVB/NJNarl wild-type mice that had undergone bilateral oophorectomy. We evaluated the fate of cryopreserved murine ovarian grafts by in vivo bioluminescent imaging (BLI), AMH mRNA expression and follicle counts.

Results

There were significantly stronger BLI signals in the fresh ovaries than in the frozen–thawed ones. The number of primordial follicles was significantly lower in frozen–thawed ovaries at 10 days after transplantation (P < 0.001). The AMH mRNA expression was significantly lower in the frozen–thawed ovaries (P < 0.001), showing that unavoidable harm occurs after transplantation.

Conclusions

Ovarian cryopreservation by slow freezing compromises ovarian reserve by cryoinjury and ischemia, evident at an early stage after transplantation.

Strategies for fertility preservation in young early breast cancer patients

Diagnosis of breast cancer in young women poses a threat to fertility. Due to a recent trend of delaying pregnancy, an increasing number of breast cancer patients in reproductive age wish to bear children. Health care providers have the responsibility to know how to manage fertility issues in cancer survivors. Oncofertility counseling is of great importance to many young women diagnosed with cancer and should be managed in a multi-disciplinary background. Most of young breast cancer patients are candidate to receive chemotherapy, which could lead to premature ovarian failure. A baseline evaluation of ovarian reserve may help in considering the different fertility preservation options. The choice of the suitable strategy depends also on age, type of chemotherapy, partner status and patients' motivation. Various options are available, some established such as embryo and oocyte cryopreservation, some still experimental such as ovarian tissue cryopreservation and ovarian suppression with GnRHa during chemotherapy. An early referral to a reproductive specialist should be offered to patients at risk of infertility who are interested in fertility preservation.

Strategies for using the sheep ovarian cortex as a model in reproductive medicine

OBJECTIVE

To evaluate and compare the distribution and density of primordial follicles within a whole sheep ovary and to gain insight into how to overcome the impact of natural follicular heterogeneity on the experimental results.

DESIGN

Histological study.

SETTING

Academic research center.

ANIMALS

Five- to nine-month-old ewes.

INTERVENTIONS

Freshly sampled whole sheep ovaries were collected and prepared for histological analysis.

MAIN OUTCOME MEASURE(S)

The follicular densities and distributions were determined for hematoxylin and eosin sections. A mathematical model was derived based on the follicle counts and Monte-Carlo simulations.

RESULTS

Heterogeneous distributions and densities of primordial follicles were identified 1) for distinct areas of the same ovarian cortex, 2) between the ovaries of the same animal and 3) across different ewes. A mathematical model based on the analysis of 37,153 primordial follicles from 8 different ovaries facilitated the estimation of the number of cortical biopsies and sections that had to be analyzed to overcome such heterogeneity.

CONCLUSION

The influence of physiological follicular heterogeneity on experimental and clinical results can be overcome when a definite number of cortical pieces and sections are taken into consideration.

Isoform 111 of vascular endothelial growth factor (VEGF111) improves angiogenesis of ovarian tissue xenotransplantation

BACKGROUND

Cryopreservation of cortex ovarian tissue before anticancer therapy is a promising technique for fertility preservation mainly in children and young women. Ischemia in the early stage after ovarian graft causes massive follicle loss by apoptosis. VEGF111 is a recently described vascular endothelial growth factor (VEGF) isoform that does not bind to the extracellular matrix, diffuses extensively, and is resistant to proteolysis. These properties confer a significantly higher angiogenic potential to VEGF111 in comparison with the other VEGF isoforms.

METHODS

We evaluated the morphology of cryopreserved sheep ovarian cortex grafted in the presence or absence of VEGF111. Ovarian cortex biopsies were embedded in type I collagen with or without VEGF111 addition before transplantation to severe combined immunodeficient mice ovaries. Transplants were retrieved 3 days or 3 weeks later. Follicular density, vasculature network, hemoglobin content, and cell proliferation were analyzed.

RESULTS

Addition of VEGF111 increased density of functional capillaries (P=0.01) 3 days after grafting. By double immunostaining of Ki-67 and von Willebrand factor, we demonstrated that proliferating endothelial cells were found in 83% of the VEGF111 group compared with 33% in the control group (P=0.001). This angiostimulation was associated with a significant enhancement of hemoglobin content (P=0.03). Three weeks after transplantation, the number of primary follicles was significantly higher in VEGF111 grafts (P=0.02).

CONCLUSION

VEGF111 accelerates blood vessel recruitment and functional angiogenesis and improves the viability of ovarian cortex by limiting ischemia and ovarian cortex damage.