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Updated: Apr 23, 2026
Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
Incidence and dosimetric parameters of pediatric brainstem toxicity following proton therapy
Daniel J Indelicato1, Stella Flampouri, Ronny L Rotondo
1Department of Radiation Oncology, University of Florida , Jacksonville, Florida , USA.
Insights
Proton therapy is safe for pediatric brainstem tumors, with low toxicity rates. Younger children and those with posterior fossa tumors may benefit from more conservative radiation doses.
Area of Science:
- Pediatric Oncology
- Radiation Oncology
- Neuro-oncology
Background:
- Proton therapy offers improved dose distribution for brain tumors compared to photon therapy.
- However, surrounding tissues can still receive significant radiation doses.
- The tolerance of the pediatric brainstem to proton therapy requires investigation.
Purpose of the Study:
- To evaluate the tolerance of the pediatric brainstem to proton therapy.
- To identify prognostic variables for brainstem toxicity.
Main Methods:
- Retrospective review of 313 pediatric patients (<18 years) treated with proton therapy for brain/skull base tumors from 2007-2013.
- Inclusion criteria: >50.4 CGE delivered to the brainstem.
- Toxicity graded using NCI Common Terminology Criteria for Adverse Events v4.0.
Main Results:
- Common histologies: ependymoma, craniopharyngioma, low-grade glioma.
- Median age: 5.9 years; median dose: 54 CGE.
- Two-year cumulative incidence of any toxicity: 3.8%; grade 3+ toxicity: 2.1%.
- Risk factors for toxicity: age <5 years, posterior fossa location, specific dosimetric parameters.
Conclusions:
- Current national brainstem dose guidelines are associated with low toxicity in pediatric patients.
- Consideration of more conservative dosimetric guidelines for young patients with posterior fossa tumors, especially after aggressive surgery.
Background:
Proton therapy offers superior low and intermediate radiation dose distribution compared with photon-based radiation for brain and skull base tumors; yet tissue within and adjacent to the target volume may receive a comparable radiation dose. We investigated the tolerance of the pediatric brainstem to proton therapy and identified prognostic variables.
Material And Methods:
All patients < 18 years old with tumors of the brain or skull base treated from 2007 to 2013 were reviewed; 313 who received > 50.4 CGE to the brainstem were included in this study. Brainstem toxicity was graded according to the NCI Common Terminology Criteria for Adverse Events v4.0.
Results:
The three most common histologies were ependymoma, craniopharyngioma, and low-grade glioma. Median patient age was 5.9 years (range 0.5-17.9 years) and median prescribed dose was 54 CGE (range 48.6-75.6 CGE). The two-year cumulative incidence of toxicity was 3.8% ± 1.1%. The two-year cumulative incidence of grade 3 + toxicity was 2.1% ± 0.9%. Univariate analysis identified age < 5 years, posterior fossa tumor location and specific dosimetric parameters as factors associated with an increased risk of toxicity.
Conclusion:
Utilization of current national brainstem dose guidelines is associated with a low risk of brainstem toxicity in pediatric patients. For young patients with posterior fossa tumors, particularly those who undergo aggressive surgery, our data suggest more conservative dosimetric guidelines should be considered.
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