Efficacy of insulin-like growth factor binding protein 3 in predicting the growth hormone response to provocative testing in children treated with cranial irradiation.
Recent data suggest that the plasma concentration of insulin-like growth factor binding protein 3 (IGFBP-3) is useful as a screening test for growth hormone (GH) deficiency. In this study, we measured by radioimmunoassay the levels of IGFBP-3 in a group of 20 subjects (12 males) of 5 years and 7 months to 16 years of age undergoing standard GH testing following cranial irradiation. The patients had received 1800 to > 6000 cGY of radiation to the hypothalamic-pituitary region, a median of 2.7 years (range 2-7 years) prior to testing. The IGFBP-3 concentrations were discordant with the results of GH testing 60% (12/20) of the time. Although IGFBP-3 levels were below the mean for age in 14 of 15 GH-deficient (peak GH < 10 micrograms/l) patients, only three of 15 GH-deficient patients had IGFBP-3 concentrations that fell below age-adjusted norms. In contrast, the IGFBP-3 levels were within the normal range in all five patients with normal GH responses. The low sensitivity (20%) of IGFBP-3 in predicting the subjects with abnormal responses was not improved by adjusting the values for bone age or stage of puberty. We concluded that a single plasma determination of IGFBP-3 is not a useful screening test for GH deficiency among patients previously treated with cranial irradiation.
Sklar
C
C
Department of Pediatrics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.
Sarafoglou
K
K
Whittam
E
E
D000293:Adolescent; D001827:Body Height; D001932:Brain Neoplasms / Q000532:radiotherapy*; D002352:Carrier Proteins / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005544:Forecasting; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D009994:Osmolar Concentration
D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone