The limited screening value of insulin-like growth factor-i as a marker for alterations in body composition in very long-term adult survivors of childhood cancer

textabstractBackground: The clinical relevance of low IGF-I levels, caused by cranial radiotherapy, in adult childhood cancer survivors has not been studied extensively. We evaluated whether IGF-I is a useful marker for altered body composition and growth hormone deficiency (GHD) in this group. Procedure: We analyzed retrospective data from 610 adult childhood cancer survivors, retrieved from the late effects clinic. Median age at diagnosis was 6 years (interquartile range 3-11) and follow-up time was 18 years (13-24). We assessed IGF-I standard deviation scores (SDS), anthropometrical measures, growth hormone stimulation tests in patients with clinical signs of GHD, and measures of body composition (assessed by dual X-ray absorptiometry, Lunar Prodigy). Results: In 58 cranially irradiated acute leukemia survivors (25 Gy (24-25)) and 56 locally irradiated brain tumor survivors (42 Gy (35-54)) we found significantly lower IGF-I SDS (P<0.001), lower height SDS (P<0.001), higher body mass index (P=0.01), higher waist-hip ratio (WHR; P=0.001), higher total fat percentage SDS (P<0.001), and lower lean body mass SDS (P