P14.101 Glioblastoma survival outcomes related to cortical/neural stem cells regions

Abstract

Abstract BACKGROUND Subventricular brain zone (SVZ) and hippocampal regions are supposed to harbor astrocyte-like neural stem cells. While some tumors may arise from transformed SVZ stem cells, other may be initiated by neo-plastic transformation of non-SVZ progenitor cells or mature glial cells. Lim′s et al classification (Neuro-Oncology 2007) of initial glioblastoma location, related to these neural stem cells regions, was predictive for invasive and multifocal tumor phenotype. The aim of this retrospective single-institutional study is to evaluate the relations of this Lim classification on survival parameters in unselected cohort of glioblastoma patients. MATERIAL AND METHODS Patients treated between 2014–2017 were grouped according to initial location of their contrast enhancing lesion as follows: Lim1 (SVZ+⋯SVZ/hippocampal involvement and Cortex+⋯cortex involvement), Lim2 (SVZ+ and Cortex-), Lim3 (SVZ- and Cortex+) and Lim4 (SVZ- and Cortex-). All patients underwent radiotherapy, some patients were indicated to full treatment according to Stupp regimen (at least 3 cycles of adjuvant chemotherapy after postsurgery chemoradiotherapy). RESULTS In total, 144 patients were analyzed (94 men, mean age 59 years). 47 patients (30.5%) were treated according to Stupp regimen. Lim1 classification was presented in 74 (48%) patients, Lim2 in 22 (14.3%), Lim3 in 50 (32.5%) and Lim4 in 8 (5.2%) patients. Cortical structures (Lim1 and Lim3) were involved in 124 (80.5%) patients. Median overall survival was significantly better in patients treated according to Stupp regimen (23.3 vs. 8.6 months, p<0.001). Median overall survival differs in respective Lim groups: 12.3, 5.6, 11.8 and 6.6 months (p=0.07). Better survival was in patients with cortical involvement (Lim1+Lim3): 12.3 vs. 6.4 months (p=0.02), especially in subgroup of patients who were not treated according to Stupp regimen (8.9 vs. 4.4 months, p=0.02) vs. those after Stupp regimen (23 vs. 23.4 months, p=0.7). CONCLUSION Initial location of enhancing glioblastoma was prognostic for overall survival, with better outcomes in patients presented by involvement of cortical structures comparing to subventricular/hippocampal zones. Molecular patterns may further clarify potential effects of neural stem cells in glioma genesis mirrored in different clinical behavior and location of initial tumor. Supported by Ministry of Health of the Czech Republic, grant No. 18-03-00469