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Exploring the Relationship Between Radiation-Induced Moyamoya Syndrome and Radiation Dose for Pediatric Patients
Gobind S Gill1, Sujith Baliga2, Jacqueline Lewy3
1Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama.
Insights
Radiation-induced moyamoya syndrome (RIMMS) incidence is low in pediatric patients treated with proton radiation therapy (PRT), with a cumulative incidence of 2.4% at 8 years. Higher doses to the optic chiasm (OC) and circle of Willis (COW) are associated with increased RIMMS risk.
Area of Science:
- Pediatric neuro-oncology
- Radiation oncology
- Cerebrovascular diseases
Background:
- Radiation-induced moyamoya syndrome (RIMMS) is a rare but serious complication.
- Understanding the incidence and risk factors of RIMMS in pediatric patients undergoing proton radiation therapy (PRT) is crucial for optimizing treatment strategies.
- Previous studies have primarily focused on photon therapy, leaving a gap in knowledge regarding PRT outcomes.
Purpose of the Study:
- To determine the incidence of RIMMS in pediatric brain tumor patients treated with intracranial PRT.
- To assess the relationship between radiation dose to the circle of Willis (COW) or optic chiasm (OC) and the development of RIMMS.
- To identify potential risk factors for RIMMS in this specific patient population.
Main Methods:
- Retrospective review of pediatric brain tumor patients treated with intracranial PRT between 1995 and 2021.
- Analysis focused on mean dose to the optic chiasm (OC) as a surrogate for dose to the COW vasculature.
- Statistical analysis included Wilcoxon rank-sum test and univariable logistic regression to evaluate the association between OC dose and RIMMS incidence.
Main Results:
- A total of 676 patients were included, with 14 developing RIMMS (median onset 1.9 years).
- The cumulative incidence of RIMMS at 8 years was 2.4%.
- Patients who developed RIMMS received a significantly higher mean OC dose (51.5 Gy) compared to those who did not (23.7 Gy).
- An OC dose exceeding 52 Gy was associated with a significantly increased risk of RIMMS (odds ratio = 9.9, P < .001).
Conclusions:
- The incidence of RIMMS in pediatric patients treated with PRT is low, comparable to rates observed with photon therapy.
- Higher radiation doses delivered to the optic chiasm (OC) and circle of Willis (COW) are significant risk factors for developing RIMMS.
- These findings underscore the importance of dose optimization to the COW and OC during PRT for pediatric brain tumors to mitigate RIMMS risk.
Purpose:
The incidence and risk factors associated with radiation-induced moyamoya syndrome (RIMMS) in pediatric brain tumor patients treated with proton radiation therapy (PRT) remain poorly understood. The objective of this study was to determine the incidence of RIMMS in the setting of central nervous system PRT in a pediatric cohort and assess its relationship with dose to the circle of Willis (COW) or optic chiasm (OC).
Methods And Materials:
We performed a retrospective review of pediatric brain tumor patients treated with intracranial PRT (1995-2021). The exposure of interest was mean dose to the OC due to close proximity to the COW vasculature. Wilcoxon rank-sum test was used to determine the association between OC dose and RIMMS. Univariable logistic regression modeling was used to determine the odds of developing RIMMS based on a cut point of 52 Gy.
Results:
Of 676 patients, 14 developed RIMMS, with a median onset of 1.9 years. The cumulative incidence of RIMMS at 8 years was 2.4%. Patients with RIMMS had a higher mean OC dose than those without (51.5 vs 23.7 Gy, P < .0001). Univariable logistic regression showed that patients with an OC dose > 52 Gy had increased RIMMS risk compared with those with a dose < 52 Gy (odds ratio = 9.9, P < .001).
Conclusions:
The incidence of RIMMS remains low in our primarily proton-treated pediatric cohort with a cumulative incidence of 2.4% over 8 years and is similar to that of photon-treated cohorts. Development of RIMMS was associated with higher doses to the COW and OC.
