IMPE Abstracts

Cumulative lifetime incidence and prevalence of endocrine abnormalities after treatment of childhood cancer increases, particularly after high-risk regimes. Both men and women experience gonadal toxicity with reduced fertility. Effects of chemotherapy and /or radiation exposure will focus on adverse effects of treatment on gonadal function, assessment of gonadal status, options for fertility preservation (FP) and risks associated with gonadal dysfunction and its treatment. For girls who have oocytes present from birth, primordial follicles sustain DNA damage, then undergo apoptosis, with reduced follicular reserve. Field radiation depletes non growing follicles. Childhood gonadotoxic treatment can interfere at any time in boys where there is an ongoing process of foetal/postnatal gonocyte differentiation to spermatogonia with an overall infertility risk 15-30% after chemotherapy, far higher after bone marrow transplant and sarcoma treatment. FP options are determined by potential toxicity of intervention, probability of relapse / further gonadotoxin exposure and, for boys, capacity to provide a semen sample. A risk stratification table can provide guidance. Options include oocyte retrieval for girls, successful use of prepubertal frozen tissue reported, sperm banking for boys or testicular biopsy and preservation for future maturation +/- re implantation. New techniques to provide better options for boys will be described. Risks associated with FP include acute surgical risks of infection, bleeding, reduced oocyte function or sperm count & quality in acute oncological illness, risks for returning leukaemic cells in transplanted tissue, risks for curtailing the limited lifespan of transplanted tissue in girls, by accelerating oocyte recruitment. Other risks include unexpected recovery from gonadal failure, resulting in unplanned pregnancy. Management options will be outlined. Secondary hypogonadism can occur in both sexes after damage to the male + female hypothalamic pituitary axis by cranial irradiation, treatment with hCG and FSH being options limited by prior depletion of gonocytes with chemotherapy and / or radiation.