2318 - Neuroanatomical Structural Changes in Irradiated Survivors of Craniopharyngioma: A Secondary Analysis of RT3CR

Purpose/Objective(s): Craniopharyngiomas often manifest with cognitive deficits due to the interplay of endocrinopathies, therapeutic interventions, and tumor location. This longitudinal study evaluates the structural changes of brain regions in children treated with proton radiotherapy (PRT) for craniopharyngioma.

Materials/Methods: A total of 296 magnetic resonance imaging (MRI) scans from 64 patients who had completed 5-year follow-up of a Phase II clinical trial were analyzed retrospectively. MRIs were collected at 5 timepoints: trial enrollment, 6 months, 1 year, 3 years, and 5 years after enrollment. Automated segmentation was conducted using the FreeSurfer recon-all clinical pipeline. Pairwise Wilcoxon rank-sum tests were performed to compare structure sizes, following which multivariable linear mixed-effects analysis was conducted to identify potential predictors of size reduction.

Results: Mean age of the study participants was 9.37 ± 4.64 years, with 50% (n = 32) being female. Median volumetric changes of the deep gray matter (GM) (1.6%), cerebellum (4.2%), corpus callosum (2.5%), and brainstem (4.5%) all demonstrated growth. However, no significant differences in structural size were noted from baseline until 5 years after treatment. Time significantly predicted growth of subcortical structures, while female sex, the number of surgical procedures, anesthesia during PRT, and tumor volume were associated with subcortical volume reduction (Table 1). Time (ß (95% CI) = -0.05 (-0.09 to -0.02); p = 0.01) and the presence of a CSF reservoir (ß (95% CI) = -0.34 (-0.63 to -0.05); p = 0.04) predicted thinning of the occipital and parietal cortices, respectively.

Conclusion: Common clinical and treatment factors are associated with a reduction in size of subcortical and cortical structures, thus negatively impacting brain structure recovery. These structural changes may guide treatment planning for future patients and help monitor strategies to mitigate cognitive effects. Clinical Trial number: NCT02792582.