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Hippocampal sparing radiotherapy for pediatric medulloblastoma : Impact of treatment margins and treatment technique

Brodin, N. Patrik ; Munck Af Rosenschöld, Per LU orcid ; Blomstrand, Malin ; Kiil-Berthlesen, Anne ; Hollensen, Christian ; Vogelius, Ivan R. ; Lannering, Birgitta ; Bentzen, Søren M. and Björk-Eriksson, Thomas (2014) In Neuro-Oncology 16(4). p.594-602
Abstract

Background. We investigated how varying the treatment margin and applying hippocampal sparing and proton therapy impact the risk of neurocognitive impairment in pediatric medulloblastoma patients compared with current standard 3D conformal radiotherapy. Methods. We included 17 pediatric medulloblastoma patients to represent the variability in tumor location relative to the hippocampal region. Treatment plans were generated using 3D conformal radiotherapy, hippocampal sparing intensity-modulated radiotherapy, and spot-scanned proton therapy, using 3 different treatment margins for the conformal tumor boost. Neurocognitive impairment risk was estimated based on dose-response models from pediatric CNS malignancy survivors and compared... (More)

Background. We investigated how varying the treatment margin and applying hippocampal sparing and proton therapy impact the risk of neurocognitive impairment in pediatric medulloblastoma patients compared with current standard 3D conformal radiotherapy. Methods. We included 17 pediatric medulloblastoma patients to represent the variability in tumor location relative to the hippocampal region. Treatment plans were generated using 3D conformal radiotherapy, hippocampal sparing intensity-modulated radiotherapy, and spot-scanned proton therapy, using 3 different treatment margins for the conformal tumor boost. Neurocognitive impairment risk was estimated based on dose-response models from pediatric CNS malignancy survivors and compared among different margins and treatment techniques. Results. Mean hippocampal dose and corresponding risk of cognitive impairment were decreased with decreasing treatment margins (P <. 05). The largest risk reduction, however, was seen when applying hippocampal sparing proton therapy - the estimated risk of impaired task efficiency (95% confidence interval) was 92% (66%-98%), 81% (51%-95%), and 50% (30%-70%) for 3D conformal radiotherapy, intensity-modulated radiotherapy, and proton therapy, respectively, for the smallest boost margin and 98% (78%-100%), 90% (60%-98%), and 70% (39%-90%) if boosting the whole posterior fossa. Also, the distance between the closest point of the planning target volume and the center of the hippocampus can be used to predict mean hippocampal dose for a given treatment technique. Conclusions. We estimate a considerable clinical benefit of hippocampal sparing radiotherapy. In choosing treatment margins, the tradeoff between margin size and risk of neurocognitive impairment quantified here should be considered.

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author
; ; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cognitive risk estimation, Hippocampal sparing, Medulloblastoma, Tumor bed boost
in
Neuro-Oncology
volume
16
issue
4
pages
594 - 602
publisher
Oxford University Press
external identifiers
  • pmid:24327585
  • scopus:84896998133
ISSN
1522-8517
DOI
10.1093/neuonc/not225
language
English
LU publication?
no
id
cf8f87cc-7156-481c-9053-2b3accb47d84
date added to LUP
2023-07-19 09:38:35
date last changed
2024-04-19 23:37:47
@article{cf8f87cc-7156-481c-9053-2b3accb47d84,
  abstract     = {{<p>Background. We investigated how varying the treatment margin and applying hippocampal sparing and proton therapy impact the risk of neurocognitive impairment in pediatric medulloblastoma patients compared with current standard 3D conformal radiotherapy. Methods. We included 17 pediatric medulloblastoma patients to represent the variability in tumor location relative to the hippocampal region. Treatment plans were generated using 3D conformal radiotherapy, hippocampal sparing intensity-modulated radiotherapy, and spot-scanned proton therapy, using 3 different treatment margins for the conformal tumor boost. Neurocognitive impairment risk was estimated based on dose-response models from pediatric CNS malignancy survivors and compared among different margins and treatment techniques. Results. Mean hippocampal dose and corresponding risk of cognitive impairment were decreased with decreasing treatment margins (P &lt;. 05). The largest risk reduction, however, was seen when applying hippocampal sparing proton therapy - the estimated risk of impaired task efficiency (95% confidence interval) was 92% (66%-98%), 81% (51%-95%), and 50% (30%-70%) for 3D conformal radiotherapy, intensity-modulated radiotherapy, and proton therapy, respectively, for the smallest boost margin and 98% (78%-100%), 90% (60%-98%), and 70% (39%-90%) if boosting the whole posterior fossa. Also, the distance between the closest point of the planning target volume and the center of the hippocampus can be used to predict mean hippocampal dose for a given treatment technique. Conclusions. We estimate a considerable clinical benefit of hippocampal sparing radiotherapy. In choosing treatment margins, the tradeoff between margin size and risk of neurocognitive impairment quantified here should be considered.</p>}},
  author       = {{Brodin, N. Patrik and Munck Af Rosenschöld, Per and Blomstrand, Malin and Kiil-Berthlesen, Anne and Hollensen, Christian and Vogelius, Ivan R. and Lannering, Birgitta and Bentzen, Søren M. and Björk-Eriksson, Thomas}},
  issn         = {{1522-8517}},
  keywords     = {{Cognitive risk estimation; Hippocampal sparing; Medulloblastoma; Tumor bed boost}},
  language     = {{eng}},
  number       = {{4}},
  pages        = {{594--602}},
  publisher    = {{Oxford University Press}},
  series       = {{Neuro-Oncology}},
  title        = {{Hippocampal sparing radiotherapy for pediatric medulloblastoma : Impact of treatment margins and treatment technique}},
  url          = {{http://dx.doi.org/10.1093/neuonc/not225}},
  doi          = {{10.1093/neuonc/not225}},
  volume       = {{16}},
  year         = {{2014}},
}