Growth hormone deficiency in adult survivors of childhood brain tumors treated with radiation

Objective: Growth hormone deficiency (GHD) is the most common endocrine late effect in irradiated survivors of childhood brain tumors. We aimed to determine the prevalence of GHD in adults treated with proton or photon irradiation for a brain tumor in childhood and to detect undiagnosed GHD. 

Design: A cross-sectional study. 

Methods: We investigated GHD in five-year survivors from two health regions in Denmark treated for childhood brain tumors with cranial or craniospinal irradiation in the period 1997–2015. Medical charts were reviewed for endocrinological and other health data. Survivors without a growth hormone (GH) test at final height were invited to a GH stimulation test. 

Results: Forty-one (22 females) survivors with a median age of 21.7 years (range 15.1 – 33.8 years) at follow up and 14.8 years (range 5.1 – 23.4 years) since diagnosis were included. Eleven were treated with proton and 30 with photon irradiation. Eighteen of 21 survivors were previously found to have GHD. Sixteen of 20 survivors with no GH test at final height were tested, 8 (50 %) had GHD. In total, 26 of 41 patients (63%) had GHD. Insulin-like growth factor-1 (IGF-1) associated poorly with the insulin tolerance test (ITT). 

Conclusion: This study identified a high prevalence of undiagnosed GHD in survivors with no GH test at final height. The results stress the importance of screening for GHD at final height in survivors of childhood brain tumors with prior exposure to cranial irradiation, irrespective of radiation modality and IGF-1.