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

Nils P. Brodin, Per Munck Af Rosenschöld, Malin Blomstrand, Anne Kiil-Berthlesen, Christian Hollensen, Ivan R. Vogelius, Birgitta Lannering, Søren M. Bentzen, Thomas Björk-Eriksson

Research output: Contribution to journalArticle

17 Citations (Scopus)

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 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.

Original languageEnglish (US)
Pages (from-to)594-602
Number of pages9
JournalNeuro-Oncology
Volume16
Issue number4
DOIs
StatePublished - 2014
Externally publishedYes

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Medulloblastoma
Proton Therapy
Radiotherapy
Pediatrics
Conformal Radiotherapy
Intensity-Modulated Radiotherapy
Therapeutics
Neoplasms
Risk Reduction Behavior
Survivors
Hippocampus
Confidence Intervals

Keywords

  • Cognitive risk estimation
  • Hippocampal sparing
  • Medulloblastoma
  • Tumor bed boost

ASJC Scopus subject areas

  • Cancer Research
  • Oncology
  • Clinical Neurology

Cite this

Brodin, N. P., Munck Af Rosenschöld, P., Blomstrand, M., Kiil-Berthlesen, A., Hollensen, C., Vogelius, I. R., ... Björk-Eriksson, T. (2014). Hippocampal sparing radiotherapy for pediatric medulloblastoma: Impact of treatment margins and treatment technique. Neuro-Oncology, 16(4), 594-602. https://doi.org/10.1093/neuonc/not225

Hippocampal sparing radiotherapy for pediatric medulloblastoma : Impact of treatment margins and treatment technique. / Brodin, Nils P.; Munck Af Rosenschöld, Per; Blomstrand, Malin; Kiil-Berthlesen, Anne; Hollensen, Christian; Vogelius, Ivan R.; Lannering, Birgitta; Bentzen, Søren M.; Björk-Eriksson, Thomas.

In: Neuro-Oncology, Vol. 16, No. 4, 2014, p. 594-602.

Research output: Contribution to journalArticle

Brodin, NP, Munck Af Rosenschöld, P, Blomstrand, M, Kiil-Berthlesen, A, Hollensen, C, Vogelius, IR, Lannering, B, Bentzen, SM & Björk-Eriksson, T 2014, 'Hippocampal sparing radiotherapy for pediatric medulloblastoma: Impact of treatment margins and treatment technique', Neuro-Oncology, vol. 16, no. 4, pp. 594-602. https://doi.org/10.1093/neuonc/not225
Brodin, Nils P. ; Munck Af Rosenschöld, Per ; Blomstrand, Malin ; Kiil-Berthlesen, Anne ; Hollensen, Christian ; Vogelius, Ivan R. ; Lannering, Birgitta ; Bentzen, Søren M. ; Björk-Eriksson, Thomas. / Hippocampal sparing radiotherapy for pediatric medulloblastoma : Impact of treatment margins and treatment technique. In: Neuro-Oncology. 2014 ; Vol. 16, No. 4. pp. 594-602.
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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 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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AU - Munck Af Rosenschöld, Per

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AU - Kiil-Berthlesen, Anne

AU - Hollensen, Christian

AU - Vogelius, Ivan R.

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AU - Björk-Eriksson, Thomas

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N2 - 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.

AB - 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.

KW - Cognitive risk estimation

KW - Hippocampal sparing

KW - Medulloblastoma

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