Seizure-susceptible brain regions in glioblastoma: identification of patients at risk.

BACKGROUND AND PURPOSE: The main aim of this study was to identify which patients with glioblastoma multiforme (GBM) have a higher risk of presenting seizures during follow-up. METHODS: Patients with newly diagnosed GBM were reviewed (n = 306) and classified as patients with (Group 1) and without (Group 2) seizures at onset. Group 2 was split into patients with seizures during follow-up (Group 2A) and patients who never had seizures (Group 2B). The anatomical location of GBM was identified and compared by voxel-based lesion symptom mapping (discovery set). Seizure-susceptible brain regions obtained were assessed visually and automatically in external GBM validation series (n = 85). RESULTS: In patients with GBM who had no seizures at onset, an increased risk of presenting seizures during follow-up was identified in the superior frontal and inferior occipital lobe, as well as in inferoposterior regions of the temporal lobe. Conversely, those patients with GBM located in medial and inferoanterior temporal areas had a significantly lower risk of suffering from seizures during follow-up. Additionally, the seizure-susceptible brain region maps obtained classified patients in the validation set with high positive and negative predictive values. CONCLUSIONS: Tumor location is a useful marker to identify patients with GBM who are at risk of suffering from seizures during follow-up. These results may help to support the use of antiepileptic prophylaxis in a selected GBM population and to improve stratification in antiepileptic clinical trials.

[Radiation-induced cognitive toxicity in adults]. / Neurotoxicidad cognitiva inducida por la radioterapia cerebral en adultos.

Cognitive toxicity induced by cranial radiation is one of the most important limitations of radiation therapy and has a significant impact on brain tumor survivors' quality of life. This review comprehends an up to date of recent studies including complete neuropsychological battery and/or advanced neuroimaging techniques. These studies identified critical anatomical and/or functional brain areas related to radiation-induced brain injury, thus improving clinical and radiological diagnosis. Pathophysiological mechanisms underlying cognitive toxicity are complex and involve different cell lines and molecules. Although there is no currently therapeutic strategy that has a demonstrated efficacy, several studies including sparing of hippocampus or the use of memantine are quite promising. A better knowledge of the characteristics of cognitive toxicity induced by cranial radiation, will help us to identify patients who will benefit from treatment and also to examine new therapeutic targets in order to improve patients' quality of life.

TITLE: Neurotoxicidad cognitiva inducida por la radioterapia cerebral en adultos.La toxicidad cognitiva inducida por la radioterapia craneal es una de las limitaciones mas importantes del tratamiento radioterapico y con mas impacto sobre la calidad de vida de los largos supervivientes de tumores cerebrales. Esta revision incluye una actualizacion del diagnostico clinico y radiologico de la toxicidad radioinducida con la incorporacion de baterias neuropsicologicas y tecnicas avanzadas en neuroimagen. Ambas herramientas han permitido en los ultimos años no solo una mejor definicion de la disfuncion cognitiva, sino tambien la identificacion de los cambios anatomicos y funcionales asociados. La fisiopatologia subyacente implica diferentes estirpes celulares y vias de señalizacion molecular, y el mecanismo es multifactorial. Aunque no existe actualmente una estrategia terapeutica que haya demostrado una clara eficacia, varios estudios, incluyendo los que proponen respetar el hipocampo o el uso de la memantina, han resultado prometedores. Profundizar en el estudio de la toxicidad cognitiva inducida por la radioterapia permitira definir mejor los pacientes que se benefician de la radioterapia, asi como estudiar nuevas dianas terapeuticas para mejorar la calidad de vida de los pacientes con daño cerebral radioinducido.

Brain functional connectivity in lung cancer population: an exploratory study.

The present study aimed to explore the functional connectivity differences in Resting State Networks (RSNs) induced by cancer and chemotherapy in Lung Cancer (LC) patients using an Independent Component Analysis (ICA). Three matched groups of 15 LC patients following Chemotherapy (C+), 15 LC patients before Chemotherapy (C-) and 15 Healthy Controls (HC) were included. Analysis was performed using ICA and a multivariate pattern analysis (MVPA) to classify groups based on profiles of functional connectivity. We found significant differences in four of the RSN identified: Default Mode Network (DMN), Predominantly Left and Right Anterior Temporal Network, and Cerebellum Network. Whereas DMN showed decreased connectivity, the other RSNs exhibited increased connectivity in both LC groups compared to HC and in C+ in comparison to C-. MVPA discriminated significantly and accurately between all groups. Our study showed that disrupted functional connectivity associated with cancer and chemotherapy-induced cognitive deficits is not only related to DMN decreased connectivity abnormalities but also to an increased connectivity of other RSNs, suggesting a potential compensatory mechanism. Graphical abstract.