ENDOCRINE FUNCTION FOLLOWING SINGLE FRACTION AND FRACTIONATED TOTAL-BODY IRRADIATION FOR BONE-MARROW TRANSPLANTATION IN CHILDHOOD

Forty-nine children who had undergone treatment with cyclophosphamide and total body irradiation before bone marrow transplantation were inv estigated for impaired endocrine function. Twenty-six patients receive d single fraction total body irradiation as a dose of 9-10 Gy, whereas 23 patients received fractionated total body irradiation as a total d ose of either 12 Gy divided into six fractions or 14.4 Gy divided into eight fractions, administered over 3 or 4 days. Half of the patients in the single fraction group and nine in the fractionated group had re ceived cranial irradiation prior to total body irradiation. Pathologic al changes in thyroid function were observed in 19 patients (73%) of t he single fraction group (elevated thyrotrophin (58%) and decreased th yroxine levels (15%)), whereas in the fractionated group only six pati ents (25%) developed transient raised thyrotrophin levels; the mean ob servation period was 3.2 years in the single fraction group and 2.7 ye ars in the fractionated group. The stimulated growth hormone peak conc entration was influenced significantly by previous cranial irradiation and was independent of the type of total body irradiation administere d. In the patients who had received cranial irradiation. the mean grow th hormone peak levels were 8.4 mU/l (single fraction group) and 1 3.9 mU/l (fractionated group), whereas in those who received only total b ody irradiation they were 24.9 mU/l (single fraction group) and 28.1 m U/l (fractionated group). The basal gonadotrophin concentration in chi ldren older than 9 years showed elevated levels in nine patients (50%) of the single fraction group and in only three patients (30%) of the fractionated group. A further 10 patients (38%) in the single fraction group and one girl (10%) in the fractionated group demonstrated abnor mal stimulated follicle stimulating hormone levels.