Normal tissue complication probability models in plan evaluation of children with brain tumors referred to proton therapy

Authors

  • Camilla H. Stokkevåg Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway;  Department of Physics and Technology, University of Bergen, Bergen, Norway
  • Daniel J. Indelicato Department of Radiation Oncology, University of Florida, Jacksonville, FL, USA
  • Klaus Herfarth Department of Radiation Oncology, University of Heidelberg, Heidelberg, Germany
  • Henriette Magelssen Department of Oncology, Oslo University Hospital, Oslo, Norway
  • Morten E. Evensen Department of Oncology, University Hospital of North Norway, Tromsø, Norway
  • Maren Ugland Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway;  Department of Physics and Technology, University of Bergen, Bergen, Norway
  • Terje Nordberg Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway;  Department of Physics and Technology, University of Bergen, Bergen, Norway
  • Tove A. Nystad Department of Oncology, University Hospital of North Norway, Tromsø, Norway
  • Camilla Hægeland Department of Oncology, University Hospital of North Norway, Tromsø, Norway
  • Mirjam D. Alsaker Department of Radiotherapy, The Cancer Clinic, St Olav’s Hospital, Trondheim University Hospital, Trondheim, Norway
  • Kjetil Ulven Department of Radiotherapy, The Cancer Clinic, St Olav’s Hospital, Trondheim University Hospital, Trondheim, Norway
  • Jon E. Dale Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway;  Department of Physics and Technology, University of Bergen, Bergen, Norway
  • Grete M. Engeseth Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway;  Department of Physics and Technology, University of Bergen, Bergen, Norway
  • Camilla G. Boer Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway;  Department of Physics and Technology, University of Bergen, Bergen, Norway
  • Laura Toussaint Department of Medical Physics, Aarhus University/Aarhus University Hospital, Aarhus, Denmark
  • Josefine S. Kornerup Department of Radiotherapy, The Cancer Clinic, St Olav’s Hospital, Trondheim University Hospital, Trondheim, Norway
  • Helge E. S. Pettersen Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway;  Department of Physics and Technology, University of Bergen, Bergen, Norway
  • Marianne Brydøy Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway;  Department of Physics and Technology, University of Bergen, Bergen, Norway
  • Petter Brandal Department of Oncology, Oslo University Hospital, Oslo, Norway
  • Ludvig P. Muren Department of Medical Physics, Aarhus University/Aarhus University Hospital, Aarhus, Denmark

DOI:

https://doi.org/10.1080/0284186X.2019.1643496

Abstract

Background: Children with brain tumors undergoing radiotherapy are at particular risk of radiation-induced morbidity and are therefore routinely considered for proton therapy (PT) to reduce the dose to healthy tissues. The aim of this study was to apply pediatric constraints and normal tissue complication probability (NTCP) models when evaluating the differences between PT and contemporary photon-based radiotherapy, volumetric modulated arc therapy (VMAT).

Methods: Forty patients (aged 1–17 years) referred from Norwegian institutions to cranial PT abroad during 2014–2016 were selected for VMAT re-planning using the original CT sets and target volumes. The VMAT and delivered PT plans were compared by dose/volume metrics and NTCP models related to growth hormone deficiency, auditory toxicity, visual impairment, xerostomia, neurocognitive outcome and secondary brain and parotid gland cancers.

Results: The supratentorial brain, temporal lobes, hippocampi, hypothalamus, pituitary glands, cochleas, salivary glands, optic nerves and chiasm received lower mean doses from PT. Reductions in population median NTCP were significant for auditory toxicity (VMAT: 3.8%; PT: 0.3%), neurocognitive outcome (VMAT: 3.0 IQ points decline at 5 years post RT; PT: 2.5 IQ points), xerostomia (VMAT: 2.0%; PT: 0.6%), excess absolute risk of secondary cancer of the brain (VMAT: 9.2%; PT: 6.7%) and salivary glands (VMAT: 2.8%; PT:0.5%). Across all patients, 23/38 PT plans had better or comparable estimated risks for all endpoints (within ±10% of the risk relative to VMAT), whereas for 1/38 patients all estimates were better or comparable with VMAT.

Conclusions: PT reduced the volumes of normal tissues exposed to radiation, particularly low-to-intermediate dose levels, and this was reflected in lower NTCP. Of the included endpoints, substantial reductions in population medians were seen from the delivered PT plans for auditory complications, xerostomia, and risk of secondary cancers of the brain and salivary glands.

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Published

2019-10-03

How to Cite

Stokkevåg, C. H., Indelicato, D. J., Herfarth, K., Magelssen, H., Evensen, M. E., Ugland, M., … Muren, L. P. (2019). Normal tissue complication probability models in plan evaluation of children with brain tumors referred to proton therapy. Acta Oncologica, 58(10), 1416–1422. https://doi.org/10.1080/0284186X.2019.1643496

Issue

Vol. 58 No. 10 (2019): Acta Oncologica

Section

Articles