Retrospective study of late radiation-induced damages after focal radiotherapy for childhood brain tumors

Abstract

Purpose To study a robust and reproducible procedure to investigate a relation between focal brain radiotherapy (RT) low doses, neurocognitive impairment and late White Matter and Gray Matter alterations, as shown by Diffusion Tensor Imaging (DTI), in children. Methods and materials Forty-five patients (23 males and 22 females, median age at RT 6.2 years, median age at evaluations 11.1 years) who had received focal RT for brain tumors were recruited for DTI exams and neurocognitive tests. Patients’ brains were parceled in 116 regions of interest (ROIs) using an available segmented atlas. After the development of an ad hoc, home-made, multimodal and highly deformable registration framework, we collected mean RT doses and DTI metrics values for each ROI. The pattern of association between cognitive scores or domains and dose or DTI values was assessed in each ROI through both considering and excluding ROIs with mean doses higher than 75% of the prescription. Subsequently, a preliminary threshold value of dose discriminating patients with and without neurocognitive impairment was selected for the most relevant associations. Results The workflow allowed us to identify 10 ROIs where RT dose and DTI metrics were significantly associated with cognitive tests results (p<0.05). In 5/10 ROIs, RT dose and cognitive tests were associated with p<0.01 and preliminary RT threshold dose values, implying a possible cognitive or neuropsychological damage, were calculated. The analysis of domains showed that the most involved one was the “school-related activities”. Conclusion This analysis, despite being conducted on a retrospective cohort of children, shows that the identification of critical brain structures and respective radiation dose thresholds is achievable by combining, with appropriate methodological tools, the large amount of data arising from different sources. This supported the design of a prospective study to gain stronger evidence.

Neurocognitive Functions Before and After Radiotherapy in Pediatric Brain Tumor Survivors

“…10,33 We mainly found lower performance among those who received doses over 50 Gy, and these were mainly embryonal tumors in cerebellum receiving WBRT and also one with PBRT (receiving both photons and protons). However, RT doses toward potential organs at risk can give more information on RT-induced neurocognitive decline than dose to planning target volume and doses below 50 Gy can also impact neurocognition 34 and will be investigated in upcoming studies. Longer time after RT was associated with lower performance on perceptual tests (matrix reasoning), working memory, and processing speed, and these functions seem to be important to measure repeatedly over time before and after RT since lower performance on same subtests seems to interact with confounding risk factors.…”

Modified Diffusion Tensor Image Processing Pipeline for Archived Studies of Patients With Leukoencephalopathy

“…The benefit of this is to achieve the research goal quickly and cost effectively. Previous retrospective studies have utilized existing DWI data sets to investigate late radiation‐induced damages after focal radiotherapy, 1 hemispheric structural network changes as a function of location and size of glioma, 2 and even the relationship between reading performance and white matter (WM) alteration and reorganization in neurosurgical patients 3 . In addition, as more and more archived data become publicly available, research can be conducted efficiently if the data can be processed in an appropriate way.…”