Strategies for Fertility Preservation in Female and Male Cancer Survivors

Fertility Preservation for Pediatric and Adolescent Patients With Cancer: Medical and Ethical Considerations

Many cancers presenting in children and adolescents are curable with surgery, chemotherapy, and/or radiotherapy. Potential adverse consequences of treatment include sterility, infertility, or subfertility as a result of gonad removal, damage to germ cells as a result of adjuvant therapy, or damage to the pituitary and hypothalamus or uterus as a result of irradiation. In recent years, treatment of solid tumors and hematologic malignancies has been modified in an attempt to reduce damage to the gonadal axis. Simultaneously, advances in assisted reproductive technology have led to new possibilities for the prevention and treatment of infertility. This clinical report reviews the medical aspects and ethical considerations that arise when considering fertility preservation in pediatric and adolescent patients with cancer.

Contemporary and future insights into fertility preservation in male cancer patients

In recent years, survival rates of cancer patients have increased, resulting in a shift of focus from quantity to quality of life. A key aspect of quality of life is fertility potential; patients suffering from iatrogenic infertility often become depressed. Since many cancer therapies—chemotherapy, radiotherapy and/or surgery—and even cancer itself have detrimental effects on the male reproductive system, it is important to preserve fertility before any treatment commences. Currently, the only reliable method of male fertility preservation is sperm banking. For patients who are unable to provide semen samples by the conventional method of masturbation, there are other techniques such as electroejaculation, microsurgical epididymal sperm aspiration and testicular sperm extraction that can be employed. Unfortunately, it is presently impossible to preserve the fertility potential of pre-pubertal patients. Due to the increasing numbers of adolescent cancer patients surviving treatment, extensive research is being conducted into several possible methods such as testicular tissue cryopreservation, xenografting, in vitro gamete maturation and even the creation of artificial gametes. However, in spite of its ease, safety, convenience and many accompanying benefits, sperm banking remains underutilized in cancer patients. There are several barriers involved such as the lack of information and the urgency to begin treatment, but various measures can be put in place to overcome these barriers so that sperm banking can be more widely utilized.

Pediatric hormonal disturbances after hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) is the treatment of choice for various malignant and nonmalignant diseases. Improvement of HSCT in children has resulted in many long-term survivors with substantial long-term morbidities. Endocrine complications are most frequently observed as late effects in HSCT recipients. Growth failure, pubertal disorders, thyroid dysfunctions, obesity, metabolic syndrome and bone loss are usually encountered after HSCT in children, while infertility is an important problem in adulthood. Patient age at HSCT, characteristics of primary diseases, intervention duration, preparative conditioning regimens, dose of irradiation and specificity of chemotherapeutic agents affect the prevalence of endocrine late effects. Awareness of endocrine late effects of HSCT and close follow-up of patients would help to increase the quality of health of patients.

Autotransplantation of cryopreserved ovarian tissue in 12 women with chemotherapy-induced premature ovarian failure: the Danish experience

OBJECTIVE

To describe a cohort of 12 Danish women who received autotransplantation of frozen-thawed cryopreserved ovarian tissue because of premature ovarian failure after cancer treatment.

DESIGN

Retrospective study.

SETTING

University hospitals.

PATIENT(S)

Twelve women with autotransplanted frozen-thawed ovarian tissue.

INTERVENTION(S)

Monitoring of hormonal parameters and results of 56 IVF cycles in 10 women.

MAIN OUTCOME MEASURE(S)

Levels of gonadotropins and sex steroids, functional life span of the grafts, and results of IVF.

RESULT(S)

All 12 women regained ovarian function between 8 and 26 weeks (mean 19 weeks) after transplantation. Ten women underwent a total of 56 IVF cycles, 76 follicles developed, 49 oocytes were aspirated, 18 were fertilized, and 16 embryos were transferred resulting in six pregnancies: two biochemical, one clinical that miscarried in week 7, and two ongoing resulting in the delivery of two healthy infants born at term to two women. One of these women subsequently conceived spontaneously and delivered another healthy infant. The life span of the transplanted tissue has been between 6 months and still functioning after 54 months.

CONCLUSION(S)

Autotransplantation consistently leads to recovery of ovarian function after treatment-induced ovarian failure. Four women became pregnant, after IVF or spontaneously, resulting in the delivery of three healthy infants.

Fertility preservation: state of the science and future research directions

OBJECTIVE

To identify issues related to fertility preservation, discuss the state of the science, and make specific recommendations to guide future research supported by the U.S. National Institutes of Health in the field of fertility preservation.

DESIGN

A 1-day meeting of an expert advisory panel convened by the Eunice Kennedy Shriver National Institute of Child Health and Human Development on January 23, 2007, at the National Institutes of Health in Bethesda, Maryland. The panelists represented the disciplines of reproductive endocrinology and infertility, urology, neurobiology, physiology, radiation oncology, pediatrics, genetics, behavioral science, surgery, and occupational health.

CONCLUSION(S)

The panel members recognized the emerging focus on fertility preservation to help women and men have biological children. Among those who might benefit from research in this area are those at risk for impaired fertility or infertility, including not only cancer survivors but also others with genetic predispositions to infertility, environmental occupational exposure to hazardous substances or conditions, or reproductive diseases such as endometriosis. The panelists highlighted the need for education and awareness among health-care providers to help people understand options for preserving fertility, the need for technologic advances, the lack of data on long-term consequences of fertility preservation, and emerging ethical and social questions. This report describes the process for developing a multidisciplinary, collaborative approach for research in this area, summarizes the discussions of the panelists, and outlines the recommendations for future research.

Preservation of fertility in pediatric and adolescent patients with cancer

Many cancers that present in children and adolescents are curable with surgery, chemotherapy, and/or radiation therapy. Potential adverse consequences of treatment include sterility, infertility, or subfertility as a result of either gonad removal or damage to germ cells from adjuvant therapy. In recent years, treatment of solid tumors and hematologic malignancies has been modified in an attempt to reduce damage to the gonads. Simultaneously, advances in assisted reproductive techniques have led to new possibilities for the prevention and treatment of infertility. This technical report reviews the topic of fertility preservation in pediatric and adolescent patients with cancer, including ethical considerations.

Progress in the development of childhood cancer therapy

Despite the continuous improvement of cancer treatment protocols, altered testicular function and infertility frequently represent major adverse effects of oncologic treatments. Thus, strong efforts are needed to avoid or at least to reduce these complications that are particularly relevant in young men without offspring. Furthermore in the last years, concerns have been raised about the possible mutagenic effect of chemotherapy on sperm. Alkylating agents are frequently and successfully used in the treatment of paediatric tumors despite their well-known gonadotoxic effect. While gonadal toxicity of cyclophosphamide has been well demonstrated, little and conflicting data are reported about the effects on testicular function of ifosfamide. The aim of this study was to compare long-term effects of ifosfamide versus cyclophosphamide based therapies, on testicular function, fertility and sperm aneuploidies in a group of 33 young males survivors of childhood cancer. Patients who had received cyclophosphamide showed a severe gonadal failure characterized by reduced testicular size, very low sperm count and some degree of Leydig cell impairment. On the contrary, in subjects who had received ifosfamide all parameters of testicular function including sperm aneuploidies were in the normal range, despite of different dose, protocol of infusion and pubertal stage at treatment. In conclusion, our results confirm data of literature reporting the high gonadal toxicity of cyclophosphamide and suggest that ifosfamide treatment seems to be safer for testicular function and fertility.

Applications of emerging technologies to the study and conservation of threatened and endangered species

Sustaining viable populations of all wildlife species requires the maintenance of habitat, as well as an understanding of the behaviour and physiology of individual species. Despite substantial efforts, there are thousands of species threatened by extinction, often because of complex factors related to politics, social and environmental conditions and economic needs. When species become critically endangered, ex situ recovery programmes that include reproductive scientists are the usual first line of defence. Despite the potential of reproductive technologies for rapidly increasing numbers in such small populations, there are few examples of success. This is not the result of a failure on the part of the technologies per se, but rather is due to a lack of knowledge about the fundamental biology of the species in question, information essential for allowing reproductive technologies to be effective in the production of offspring. In addition, modern conservation concepts correctly emphasise the importance of maintaining heterozygosity to sustain genetic vigour, thereby limiting the practical usefulness of some procedures (such as nuclear transfer). However, because of the goal of maintaining all extant gene diversity and because, inevitably, many species are (or will become) 'critically endangered', it is necessary to explore every avenue for a potential contributory role. There are many 'emerging technologies' emanating from the study of livestock and laboratory animals. We predict that a subset of these may have application to the rescue of valuable genes from individual endangered species and eventually to the genetic management of entire populations or species. The present paper reviews the potential candidate techniques and their potential value (and limitations) to the study and conservation of rare wildlife species.