Trajectories of Cortical Atrophy Differ According to Cognitive Phenotype in Adults With Primary Brain Tumors

This study investigated patterns of cortical atrophy longitudinally in a prospective cohort of well-characterized patients with primary brain tumors before radiation therapy (RT) and at discrete time points up to 1-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.

Adults (aged 20-72 years) with primary brain tumors were enrolled in a prospective, observational study examining the effects of fractionated, partial brain RT on brain structure and cognition (n = 85). Cortical atrophy rates were compared using multilevel modeling across 4 different time points (baseline, 3, 6, and 12 months after RT) between minimal, generalized, and isolated verbal memory impairment phenotypes taken from a previous study's latent profile analysis.

The minimal impairment phenotype showed no regions of significant change in cortical thickness across the 4 time points analyzed. The generalized impairment phenotype showed bihemispheric, multilobar 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 the 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% to 8.7% compared with baseline.

In patients with primary brain tumors, the cognitive profile before 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.