Temporal lobe cortical thickness and cognition in paediatric cancer survivors previously treated with chemotherapy

Summary Long‐term neurocognitive outcomes in paediatric cancer survivors treated with chemotherapy remain incompletely characterized, particularly in relation to cortical structure. Prior neuroimaging studies have included limited representation of racial and ethnic minority survivors. We analysed temporal lobe cortical thickness and cognition in paediatric cancer survivors treated with chemotherapy ( n = 21; 8–25 years post‐chemotherapy; aged 15–34 years) and age‐matched controls ( n = 21). Cognition was assessed using National Institute of Health (NIH) Toolbox scores. Cortical thickness of nine bilateral temporal regions was derived from T1‐weighted 3T magnetic resonance imaging (MRI) using FreeSurfer. Group differences and brain–cognition associations were analysed using adjusted regression models with false discovery rate correction. Survivors scored lower on crystallized ( p < 0.001), fluid ( p = 0.013) and total cognition scores ( p = 0.001). They showed reduced temporal lobe cortical thickness (2.62 ± 0.13 vs. 2.74 ± 0.11 mm; p = 0.001), with reductions in seven subregions. Greater thickness was associated with better cognitive performance in 10 of 27 associations, most prominently for crystallized cognition. Fully corrected T ‐score sensitivity analyses showed crystallized cognition remained lower in survivors ( p = 0.044). Paediatric cancer survivors previously treated with chemotherapy showed reduced temporal lobe cortical thickness, which was associated with worse crystallized cognition, suggesting a potential structure–function association.