Precocious and premature puberty associated with treatment of acute lymphoblastic leukaemia

Early puberty in 28 children (23 girls, five boys) treated for acute lymphoblastic leukaemia (ALL) at a mean age of 4.0 years (range 1.4-7.8) is described. All but one had received prophylactic cranial irradiation (1800-2400 cGy) and three children had received additional cranial or craniospinal irradiation as treatment for relapse of their leukaemia. Mean age for the onset of puberty was 8.8 (SD 0.8) years in the girls and 9.3 (0.8) years in the boys; this is greater than two standard deviations from the mean for normal girls and boys. Five children (three girls, two boys) had precocious puberty. The onset of puberty occurred at greater than two standard deviations from the mean for normal girls and boys in 14(13%) girls and 4(3%) boys treated at less than eight years of age between 1970 and 1985. In a group of 55 girls treated for ALL who had survived in first remission for six years or more from diagnosis, there was a relation between young age at onset of treatment and early menarche. We suggest that premature activation of the hypothalamic-pituitary-gonadal axis occurs as a consequence of hypothalamic dysfunction due to cranial irradiation. Precocious and premature puberty in children treated for ALL may be an important factor in contributing to short stature.