Male fertility and strategies for fertility preservation following childhood cancer treatment

Infertility in the male is a potential complication of childhood cancer treatment for long-term survivors. The risk is dependent primarily on the treatment used, but also on the underlying disease. Chemotherapy (especially alkylating agents) and radiotherapy, even in low doses, may damage the seminiferous epithelium and impair spermatogenesis in both children and adults. Leydig cell function and testosterone production are generally preserved after chemotherapy and low dose radiotherapy, whilst larger doses of radiotherapy may result in hypogonadism. Patients treated with potentially gonadotoxic treatments require regular multidisciplinary follow-up including assessment of puberty and gonadal function. Currently the only option available for fertility preservation in young males treated for cancer is semen cryopreservation. For pre-pubertal patients, techniques for fertility preservation remain theoretical and as yet unproven. These include hormonal manipulation of the gonadal environment before treatment, germ cell transplantation and testis xenografting, which have all shown promise in a variety of animal studies. Refinement of these techniques requires investigations in relevant animal models. In the present chapter we include data which suggest that the common marmoset (Callithrix jacchus) monkey, a New World primate, exhibits important parallels with human testicular development and may help us to understand why the pre-pubertal testis is vulnerable to effects of cytotoxic therapy on future fertility.