ESTRO 2024 - Abstract Book

S828

Clinical - CNS

ESTRO 2024

Stam, C. J. (2014). Modern network science of neurological disorders. In Nature Reviews Neuroscience (Vol. 15, Issue 10). https://doi.org/10.1038/nrn3801

1145

Digital Poster

Hippocampal Dosimetry and Neurocognitive Function in Patients undergoing Stereotactic Radiosurgery

Najmus S Iqbal 1,2 , Michelle Smalley 3 , Tara Daisley-Devoy 4 , Maeve Williams 5 , John N Staffurth 1,2 , Jillian Maclean 1 , James R Powell 1 1 Velindre University NHS Trust, Clinical Oncology, Cardiff, United Kingdom. 2 Cardiff University, School of Medicine, Cardiff, United Kingdom. 3 Cwm Taf University Health Board, Clinical Psychology, Cardiff, United Kingdom. 4 University of Bath, Clinical Psychology, Bath, United Kingdom. 5 Velindre University NHS Trust, Medical Physics, Cardiff, United Kingdom

Purpose/Objective:

Patients with brain metastases can develop impaired neurocognitive function (NCF) following treatments such as whole brain radiotherapy, stereotactic radiosurgery (SRS) and neurosurgical resection. Randomised controlled trials have demonstrated that patients undergoing SRS alone have reduced risk of developing NCF impairment compared to those who had WBRT and SRS (1, 2). Despite the precision of SRS, a recent clinical trial has demonstrated that up to 60% of patients may still develop NCF impairment following treatment with SRS alone (1). One proposed mechanism of NCF impairment following radiotherapy to the brain involves hippocampal damage. There is evidence from primary brain tumour studies that a dose of 7.3 Gy to more than 40% of the bilateral hippocampi is associated with significant NCF impairment (3). In patients with brain metastases undergoing WBRT, techniques for hippocampal avoidance using modern radiotherapy techniques, to limit the dose to the hippocampus, have been proposed (4).

To study this in more detail we designed a prospective observational study to measure NCF before and after SRS in patients with 1-3 brain metastases and correlated NCF changes with hippocampal dosimetry.

Material/Methods:

Patients underwent NCF testing at baseline, 1-, 3- and 6-months following SRS and quality of life (QoL) was measured at each time point. NCF testing consisted of Hopkins learning verbal test – revised (HVLT-TR), trail making test, controlled oral word association test and digit span as recommended by the response assessment in neurology (RANO) group. QoL was measured using the European organisation for research and treatment of cancer core quality of life questionnaire (EORTC QLQ-C30) questionnaires at each time point. The radiation therapy oncology group (RTOG) 0933 protocol was utilised to delineate hippocampal volumes (5). Fisher exact test was performed to test statistical significance. Multivariate analysis was conducted looking at confounding factors, in particular standard brain dose parameters.