Dosimetry and growth hormone deficiency following cranial irradiation of childhood brain tumors

Research output: Contribution to journalArticle

Abstract

Background. Dosimetry of the hypothalamus-pituitary (HP) region could allow prediction of the risk of growth hormone deficiency (GHD) following cranial irradiation.
Procedure. Nineteen children (15 boys) with a median age of 6.3 years (range 1.7–16.5) at the time of irradiation of a brain tumor not involving the HP axis were followed for 1.2–6.3 years (median 3.4) from radiotherapy (RT). The dose to a standardized anatomical model including the HP region was calculated from dose volume histograms of 10% to 100% in steps of 10% of the HP model based on data from a computer-based treatment planning system. If GHD was suspected from insulin-like growth factor-I, serum insulin-like growth factor binding protein-3, and/or height velocity measurements, an arginine stimulation test was performed. GHD was defined by a peak GH <15mU/liter.
Results. Ten patients developed GHD 10–26 months from irradiation. Cox regression analysis identified the 90% dose volume of the HP box as the strongest predictor of development of GHD (P = 0.03). The median dose to the 90% dose-volume of the HP region was 37.5 Gy (range 2.3–55.3). The cumulated risk of GHD 2.5 years after radiotherapy for children receiving more than and less than 37.5 Gy to the HP region was 87% and 33%, respectively (P = 0.036).
Conclusions. Dosimetry of a defined HP volume provides the opportunity to 1) calculate the exact dose delivered to this region, 2) predict the risk of GHD and, 3) in the future revise the treatment planning and thus reduce the risk of endocrine adverse effects.

Details

Authors
  • Marianne Schmiegelow
  • Sören Lassen
  • Lars Weber
  • Hans Skovgaard-Poulsen
  • Henrik Hertz
  • Joern Müller
External organisations
  • External Organization - Unknown
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Radiology, Nuclear Medicine and Medical Imaging

Keywords

  • radiotherapy, late effects, childhood cancer, dosimetry, growth hormone deficiency, insulin-like growth factor
Original languageEnglish
Pages (from-to)564-571
JournalMedical and Pediatric Oncology
Volume33
Issue number6
Publication statusPublished - 1999
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes