Long-term effects of cranial irradiation on endocrine function in children with brain tumors. A prospective study.

This study prospectively evaluated the endocrine function of 11 children treated with cranial irradiation (CRT) for brain tumors. All tumors were remote from the hypothalamic-pituitary axis. Children were studied before treatment and at 3, 6, and 12 months after the completion of CRT. T4, thyroid-stimulating hormone, prolactin, plasma cortisol, and urinary follicle-stimulating hormone and luteinizing hormone values were normal before and after treatment in all patients. Growth hormone (GH) deficiency was identified in 0 of 7 patients before treatment, in 2 of 7 patients 3 months post-CRT, in 9 of 11 patients 6 months post-CRT, and in 7 of 8 patients 12 months post-CRT. Growth deceleration was identified in five of seven prepubertal patients. GH deficiency is an extremely common sequelae of CRT, beginning as early as 3 months after the completion of CRT. The deficit is progressive over time.