Selective Vulnerability of Cerebral Cortex Regions to Radiation Dose–Dependent Atrophy

Abstract

in patients 18 years (n Z 13), with 2-year OS of 85.7% vs. 50.0% (HR Z 0.08; 95% CI Z 0.01-0.80; P Z 0.032) and for patients >18 years (n Z 184), with 2-year OS of 95.0% vs. 76.5% (HR Z 0.54; 95% CI Z 0.30-0.97; P Z 0.039), respectively. At 30 months, all patients 18 years who had not received RT had died. Conclusion: PORT appears to improve OS in both pediatric and adult patients with papillary meningioma in this population-based analysis and should therefore be considered in those who present with this rare, aggressive tumor.

Regional susceptibility to dose-dependent white matter damage after brain radiotherapy

“…Elucidation of regional white matter sensitivity within the context of neural networks of memory and higher-order cognition is critical to understanding the pathogenesis of radiation-induced cognitive decline, as well as informing studies on cognitive-sparing RT. The white matter regions identified in the current study have close interplay with the hippocampal network and association cortex that also appear to be dose-sensitive [30,31], supporting the idea that damage within these networks may mediate the neurocognitive sequelae of brain radiotherapy.…”

Altered Network Topology in Patients with Primary Brain Tumors After Fractionated Radiotherapy

“…The relationship between dose and decreased clustering coefficient suggests that higher doses of RT lead to a greater disruption of local network connectivity both within and across regions. In addition, we identified several regions (including the IPL, PC, and RAC) that appear to be highly vulnerable to RT (Seibert et al, 2016). This finding is of par-ticular interest given the importance of the IPL and RAC to the well-described central executive network (CEN)-a network of fronto-cingulo-parietal regions that subserves a broad range of executive functions, including sustained attention, mental flexibility, inhibition, and working memory (Niendam et al, 2012).…”

“…However, less attention has been given to neocortical atrophy; until recently, the neocortex was thought to be radioresistant. Recent research has shown widespread RT-induced atrophy to association cortex (Karunamuni et al, 2016;Kim et al, 2004), and there is emerging evidence that cortical atrophy is dose dependent and most pronounced in temporo-limbic and parietal regions (Karunamuni et al, 2016;Seibert et al, 2016). Karunamuni and colleagues (2016) demonstrated cortical thinning of up to 0.3 mm in the highest dose regions 1 year post-RT, which exceeds the annual atrophy rate (0.07-0.1 mm) observed in patients with Alzheimer's disease (AD) (Sabuncu et al, 2011;Thompson et al, 2003).…”

“…We applied graph theory to MRI-derived cortical thickness estimates of 54 patients with primary brain tumors before and after RT. We selected cortical thickness as our metric of interest due to previous literature demonstrating the sensitivity of this measure to both radiation injury (Karunamuni et al, 2016;Seibert et al, 2016) and vulnerability in other patient populations (He et al, 2008;Li et al, 2012). We examined both global and local changes in network topology and analyzed the effects of regional RT dose on local network properties.…”