Trajectories of cortical atrophy differ according to cognitive phenotype in adults with primary brain tumors.

Abstract

Purpose: This study investigated patterns of cortical atrophy longitudinally in a prospective cohort of well-characterized patients with primary brain tumors before radiotherapy (RT) and at discrete timepoints up to one-year post-RT. Patients with more impaired profiles were hypothesized to show greater and more widespread atrophy post-RT than patients with minimally-impaired profiles.

Methods and materials: Adults with primary brain tumors aged 20-72 years were enrolled in a prospective, observational study examining effects of fractionated, partial brain radiotherapy on brain structure and cognition (n=85). Cortical atrophy rates were compared using multilevel modeling with four timepoints (baseline, 3-, 6-, 12-months after RT) between minimal, generalized, and isolated verbal memory impairment phenotypes, derived in a prior study through latent profile analysis.

Results: The minimal impairment phenotype showed no regions of significant change in Cortical Thickness (CT) across the 4 time points analyzed. The generalized impairment phenotype showed bi-hemispheric, multi-lobar cortical atrophy, with the greatest changes observed in the left precentral gyrus, lateral occipital cortex, and frontal pole. The verbal memory impairment phenotype demonstrated less extensive atrophy focally in left superior temporal and superior parietal cortices. Annualized atrophy rates in regions of significant cortical thinning in the generalized and verbal memory impairment phenotypes ranged from 3.5-8.7% compared to baseline.

Conclusions: In patients with primary brain tumors, cognitive profile prior to RT informs the pattern and risk for RT-related cortical atrophy. Cognitive profiles may aid in identifying patients at greater risk for RT-related atrophy and accelerated cognitive decline.