RADT-03. IDENTIFYING BRAIN STRUCTURES LINKED TO RADIATION-INDUCED ENDOCRINE AND COGNITIVE SEQUELAE: A MULTI-CENTRE VOXEL-BASED ANALYSIS

Abstract

Abstract BACKGROUND Radiotherapy (RT) is a common treatment for paediatric brain tumours. Despite advancements in techniques to mitigate RT-induced toxicity, almost two-thirds of patients develop long-lasting endocrine and cognitive sequalae. Image-based data mining (IBDM) is a voxel-based analysis tool that can identify dose-sensitive regions, supporting development of tailored radiation treatments for future patients that avoids these regions. We present the first IBDM study localising endocrine and cognitive effects in paediatric brain tumour patients. METHODS Imaging (MRI and CT) and clinical data were available for 261 children (146 medulloblastoma patients in centre A, 115 patients with mixed diagnoses in centre B). Outcomes were reported as Growth Hormone Deficiency (GHD, presence/absence, both centres) and processing speed (PS, continuous slope derived from a linear mixed-effects model, centre A). IBDM evaluated where dose was associated with outcome (p-value<0.01). Mean dose to this region was included in multivariable analysis adjusting for age, risk status, hydrocephalus status/management, and chemotherapy. RESULTS GHD was associated with dose to a region overlapping the pituitary and brainstem. In centre A, multivariable analysis revealed a 13(2-27)% average increase in GHD odds per 1Gy increase in dose, with an inverse effect for age. Center B showed a 8(4-13)% average increase for every 1Gy, with no other predictors. For PS, a central frontal region from the medial frontal lobes to the hypothalamus was identified (139 patients in centre A). Every 1Gy increase led to a -0.08(-0.20 – 0.04) PS change, with age and hydrocephalus management as contributing factors. CONCLUSION We identified a region (encompassing the pituitary and brainstem) associated with increased risk of GHD, that was consistent in two independent cohort analyses. Furthermore, PS decline was linked to dose to a frontal region. Minimising dose to these regions for future patients could reduce the risk of cognitive and endocrine sequelae.