Fertility Preservation in Cancer and Medical Illness

Fertility preservation refers to the methods used to safeguard the future reproductive potential of people whose fertility is threatened by age, by gonadotoxic medical treatment such as chemotherapy or radiotherapy, or by other illness. Established options include cryopreservation (freezing) of sperm, oocytes (eggs), or embryos, while ovarian tissue cryopreservation has progressed from experimental to a recognized technique, particularly for prepubertal patients.

Definition

Fertility preservation is the set of clinical strategies — chiefly cryopreservation of sperm, oocytes, embryos, or gonadal tissue — undertaken to retain the possibility of future biological parenthood when fertility is at risk from gonadotoxic therapy, disease, or age.

Scope

This topic surveys why and when fertility preservation is considered, the principal techniques and their biological basis, and the populations for whom each applies. It is a reference overview of methods and evidence and does not give individualized treatment recommendations.

Core questions

• Which patients are candidates for fertility preservation, and when in their care should it be considered?
• What are the established versus emerging preservation techniques for males and females?
• How does ovarian tissue cryopreservation differ from oocyte or embryo freezing?
• What biological and practical constraints shape the choice of method?

Key concepts

• Gonadotoxic therapy
• Sperm cryopreservation
• Oocyte cryopreservation
• Embryo cryopreservation
• Ovarian tissue cryopreservation
• Oncofertility
• Prepubertal fertility preservation

Mechanisms

Chemotherapy and radiotherapy can deplete the ovarian follicle pool or damage the testicular germinal epithelium, so preservation aims to bank gametes or gonadal tissue before treatment. In males, sperm cryopreservation is the standard, established option. In post-pubertal females, controlled ovarian stimulation followed by oocyte or embryo cryopreservation is standard; ovarian tissue cryopreservation removes and freezes cortical tissue containing primordial follicles for later autotransplantation, an approach especially relevant when stimulation is not feasible or when the patient is prepubertal (Sonmezer & Oktay, 2004; Smitz et al., 2010). Research into in vitro follicle growth and maturation seeks to derive mature oocytes from preserved tissue without reintroducing disease-bearing cells (Smitz et al., 2010).

Clinical relevance

Fertility preservation is integrated into cancer care so that potentially gonadotoxic treatment does not foreclose future parenthood, and professional guidelines recommend that clinicians discuss the possibility with patients of reproductive age before such treatment begins. This entry describes methods and evidence for reference; decisions about whether and how to pursue preservation are individualized and belong to the treating team.

Epidemiology

Improving survival from cancers that affect children and young adults has expanded the population living long enough to face treatment-related infertility, increasing demand for preservation services. Uptake varies with awareness, timing relative to urgent treatment, access, and cost.

Evidence & guidelines

The American Society of Clinical Oncology clinical practice guideline update recommends early discussion of fertility preservation with patients of reproductive age and describes available options (Oktay et al., 2018). Reviews summarize techniques for female preservation and the maturation of ovarian tissue cryopreservation from experimental toward established status (Sonmezer & Oktay, 2004; Smitz et al., 2010).

History

Sperm banking has been available since the mid-twentieth century, but female options lagged because eggs are difficult to freeze. The advent of reliable embryo cryopreservation, then oocyte vitrification, and the first live births after ovarian tissue autotransplantation in the 2000s, transformed the field and gave rise to oncofertility as a recognized clinical and research domain.

Debates

Where does ovarian tissue cryopreservation stand?

Once labeled experimental, ovarian tissue freezing and autotransplantation has produced live births and is increasingly considered established, especially for prepubertal patients, while questions about reintroducing malignant cells and optimizing in vitro follicle growth remain under study.

Seminal works

• oktay-2018
• sonmezer-2004
• smitz-2010

Frequently asked questions

Who is fertility preservation for?

It is considered for people of reproductive age whose fertility may be reduced by gonadotoxic treatment such as chemotherapy or radiotherapy, by certain illnesses, or by anticipated age-related decline; guidelines recommend discussing it before such treatment begins.

How is fertility preserved in a prepubertal child?

Because prepubertal children cannot produce mature gametes, ovarian tissue cryopreservation (and, for boys, testicular tissue approaches that remain largely experimental) is used to bank gonadal tissue containing immature germ cells for potential future use.