Study On The Relationship Between The Location Characteristics Of Glioma And The Age And Prognosis Of Patients

Section I:Distribution and age-associated brain regions in gliomasObjectiveTumor location and age of patients are both associated with tumor origin, genetic characteristics, and prognosis. The objective of this study is to map the distribution of glioma and investigate the relationship between tumor location and age at diagnosis in a large cohort of patients.MethodsWe enrolled a cohort of 200 adults with glioblastoma multiforme (GBM) and another cohort of 200 adults with diffuse low-grade glioma (LGG). All tumors were manually segmented on magnetic resonance images of patients and then registered to a standard brain space. By using voxel-by-voxel regression analysis, specific brains regions associated with advanced age at tumor diagnosis were localized.ResultsOverlay map indicated LGG was prone to involve the left frontal and bilateral temporal lobe; GBM occurred more frequently at left frontal lobe, temporal lobe and bilateral parietal lobe. In both groups, tumors were associated with the subventricular zone (SVZ). In the LGG cohort, the brain regions associated with advanced age at tumor diagnosis were mainly located in the right middle frontal region, while a region in the left temporal lobe, particularly at the SVZ, was associated with lower age at tumor diagnosis. In the GBM cohort, the brain regions associated with advanced age at tumor diagnosis were mainly located in the temporal lobe, particularly at the posterior region of the SVZ. A region in the left inferior frontal region was associated with lower age at tumor diagnosis. Significant differences in the age of patients were found between tumors located in the identified regions and those located elsewhere in both cohorts.ConclusionsThe current study mapped the distribution of glioma and demonstrated the correlation between tumor location and age at diagnosis, which implies differences in the origin of gliomas in young and older patients.Section Ⅱ:Association of the subventricular regions with survival outcomes in patients with gliomaObjectiveThe subventricular zone (SVZ), suggested to preferentially harbor neural stem cells, the potential precursors of cancer stem cells in the neural system, has been implicated in the origination, development, and biological behavior of gliomas. The current study aimed to investigate the prognostic role of SVZ involvement in lower-grade glioma.MethodsTo that end, we reviewed 143 patients with diffuse astrocytomas (DA) and 160 patients with anaplastic gliomas (AG). Tumor lesions were manually delineated on magnetic resonance, then qualitative and quantitative analysis was performed to investigate the prognostic role of SVZ-involvement in lower-grade gliomas.ResultsIn the group of DA, we found SVZ contact with tumors to be a significant prognostic factor of overall survival in all patients (p= 0.027). In the SVZ-involved cohort, a shorter distance from the tumor centroid to the SVZ (≤30 mm) correlated with shorter overall survival (p= 0.022) on univariate analysis. However, there was no significant difference in overall survival with respect to the SVZ region involved with the tumor (p= 0.930). Multivariate analysis showed that a shorter distance between the tumor centroid and the SVZ (p= 0.039) was significantly associated with poor overall survival in SVZ-involved patients.For the group of AG, univariate analysis indicated SVZ involvement significantly correlated with progression-free survival (p= 0.021) and overall survival (p<0.001). Multivariate analysis showed that SVZ involvement was an independent prognostic factor for unfavorable survival (p= 0.016 for overall survival), as was the involvement of the occipital horn of the SVZ (p<0.001 for progression-free survival, and p= 0.016 for overall survival).ConclusionsThe current study helps establish the prognostic role of SVZ involvement in DA and AG. Our results could provide supports for future basic research and clinical applications.