Cranial irradiation does not result in pituitary–gonadal axis dysfunction in very long-term male survivors of childhood acute lymphoblastic leukemia

Abstract Abstract 989 Poster Board I-11 Introduction: One of the risks of childhood cancer treatment is fertility impairment later in life. In the past a large proportion of children with acute lymphoblastic leukemia (ALL) has received cranial irradiation as part of their treatment. The aim of this study was to evaluate whether cranial irradiation negatively affects pituitary regulated gonadal function in male survivors of childhood ALL. Patients and Methods: We examined gonadal function, including Inhibin B, LH, FSH, testosterone, and pituitary axis function by measuring TSH, Free-T4 and IGF-I levels in 89 long-term male survivors of childhood ALL after a median follow-up time of 19 year (range 7-34 years). Results: Twenty-nine out of 89 male ALL survivors received cranial irradiation. Inhibin, FSH, LH, Testosterone, testicular volume as well as TSH and Free-T4 levels were not different in the cranial irradiated group as compared to the non-irradiated group (table 1). In contrast, IGF-I levels were significantly lower in the cranial irradiated group. Survivors treated with total body irradiation or testicular irradiation had significantly decreased gonadal function based on hormone levels. Conclusions: These data show that, in contrast to the negative influence on the growth hormone axis, cranial radiotherapy as part of ALL treatment does not have a deleterious long-term effect on the hypothalamic–pituitary-gonadal axis or pituitary-thyroid axis. Disclosures: No relevant conflicts of interest to declare.