Beyond tumor location: Global neurostructural reshaping in patients with left brain tumors

2125 

Abstract Submission 

Lucia Manso-Ortega^1,2, Santiago Gil-Robles^3,4,5, Iñigo Pomposo^6,5, Garazi Bermudez^6,5, Lucía Amoruso^7,8, Iago Rego-García^9,2,10, Manuel Carreiras^7,2,8, Ileana Quinones^7,11

¹Basque Center of Cognition, Brain and Language, San Sebastián, Gipuzkoa, ²University of the Basque Country (UPV-EHU), Bilbao, Spain, ³Universitary Hospital Quironsalud Madrid, Madrid, Madrid, ⁴BioCruces Research Institute, Bilbao, Spain, ⁵Universitary Hospital Cruces, Bilbao, Spain, ⁶BioCruces Research Institute, Bilbao, Bilbao, ⁷Basque Center on Cognition, Brain and Language, San Sebastián, Gipuzkoa, ⁸IKERBASQUE. Basque Foundation for Science, Bilbao, Spain, ⁹BioGipuzkoa Health Research Institution, San Sebastián, Gipuzkoa, ¹⁰Osakidetza, Organización Sanitaria Integrada (OSI) Goierri-Urola Garaia, Gipuzkoa, Spain, ¹¹BioGipuzkoa Health Research Institution, Gipuzkoa, Spain

Lucia Manso-Ortega  
Basque Center of Cognition, Brain and Language|University of the Basque Country (UPV-EHU)
San Sebastián, Gipuzkoa|Bilbao, Spain

Santiago Gil-Robles  
Universitary Hospital Quironsalud Madrid|BioCruces Research Institute|Universitary Hospital Cruces
Madrid, Madrid|Bilbao, Spain|Bilbao, Spain

Iñigo Pomposo  
BioCruces Research Institute|Universitary Hospital Cruces
Bilbao, Bilbao|Bilbao, Spain

Garazi Bermudez  
BioCruces Research Institute|Universitary Hospital Cruces
Bilbao, Bilbao|Bilbao, Spain

Lucía Amoruso  
Basque Center on Cognition, Brain and Language|IKERBASQUE. Basque Foundation for Science
San Sebastián, Gipuzkoa|Bilbao, Spain

Iago Rego-García  
BioGipuzkoa Health Research Institution|University of the Basque Country (UPV-EHU)|Osakidetza, Organización Sanitaria Integrada (OSI) Goierri-Urola Garaia
San Sebastián, Gipuzkoa|Bilbao, Spain|Gipuzkoa, Spain

Manuel Carreiras  
Basque Center on Cognition, Brain and Language|University of the Basque Country (UPV-EHU)|IKERBASQUE. Basque Foundation for Science
San Sebastián, Gipuzkoa|Bilbao, Spain|Bilbao, Spain

Ileana Quinones  
Basque Center on Cognition, Brain and Language|BioGipuzkoa Health Research Institution
San Sebastián, Gipuzkoa|Gipuzkoa, Spain

Brain tumors are known to disrupt cognitive functions according to their location. Following this idea, studies examining the structural impact of brain tumors have primarily focused on lesion location and their immediate counterparts, overlooking the dynamic interplay within brain networks. These studies have found effects in the grey matter volume of the contralesional hemisphere [1]–[3], restricted to changes in volume in the immediate contralesional region without providing any insights for the rest of the brain. In a previous study, to actually take into account the impact within a certain network, we studied patients with tumors in the left hemisphere and focused on grey matter volume of 10 language related regions and found changes for all of them in contrast to healthy participants, regardless of tumor location [4].

Consequently, this research aimed at assessing whether the presence of a tumor within the left hemisphere induced structural reshaping across the entire brain. For this purpose, we included a cohort of 39 patients with a tumor within the left hemisphere (including frontal, SMA, temporal, and parietal lesions) that were recorded in the pre-surgical stage and the longitudinal assessment of 22 of those patients 3 months after surgery. As a control, we include the data of 70 healthy participants. All participants underwent cognitive evaluations, including measures of general cognitive state, intelligence and working memory. Regarding language abilities, we obtained measures for language production, language comprehension and grammatical use. Patients completed the evaluations before and after surgery. To explore the mechanisms for structural plasticity, we collected high-resolution MRI T1 and T2 - weighted images. For patients, these images were collected before and after surgery and the lesion affected-area was manually reconstructed slice by slice in the native space by trained technicians. The overlay map by tumor location can be seen in Figure 1A. As an index of macrostructural alterations, we measured grey matter volume through voxel-based morphometry analysis (VBM) [5]. As a spatial constraint, we parcellated the brain according to the automatic labeling atlas (AAL)[6].

Results stated that, in comparison to healthy participants, patients showed volumetric decreases not only in the immediate contralesional area, as suggested by other studies, but also in the vicinity of the tumor and throughout the entire contralateral hemisphere. These results are illustrated in Figure 1B with controls depicted in dashed lines. This demonstrates that the structural effects of a brain tumor are global rather than lesion location dependent. Interestingly, patients showed no longitudinal difference in grey matter volume in either of the hemispheres 3 months after the surgical intervention. A lack of changes in volume after the tumor resection suggests that neuroplasticity mechanisms were happening already at the presurgical stage, most likely due to the nature of the lesion, which growth allows for reorganization.

Thus, by revealing a global pattern in the decrease of grey matter volume, this study challenges the traditional localizationist strategy followed when conducting structural studies in patients with brain tumors. A change is needed from studying just the contralesional area towards considering a whole-brain approach to understand the actual macrostructural impact. Overall, our findings shed light on the extent of the structural changes caused by the presence of a brain tumor, emphasizing the need to extend the scope of presurgical and intraoperative brain mapping in patients with brain tumors since the impact of a brain lesion appears to be global. Intraoperative mapping should be designed to respect the anatomical substrate that is already going through neuroplastic processes, moving to holistic treatments that would lead us to promote recovery and ultimately minimize the long-term deficits.

Language Comprehension and Semantics

Other Methods

Cortical Anatomy and Brain Mapping ¹

Neuroanatomy Other ²

Cognition

Cortex

Language

Plasticity