Is Edema Zone Volume Associated With Ki-67 Index in Glioblastoma Patients?

Introduction Despite all the progress with genetic mapping and multimodal treatment, the prognosis of Glioblastoma multiforme (GBM) remains poor, with median overall survival (OS) of only 12 to 15 months. Several studies showed correlations between glioblastoma clinic and prognosis factors; however, it doesn`t occur with tumor radiological features. The purpose of this study is to determine possible correlations between the volumetric analysis of glioblastoma compartments and the proliferation index represented by Ki-67. Methods We performed a retrospective analysis of MRI studies of 70 patients with glioblastoma multiforme acquired up to one week before surgery. The tumor compartments were divided into enhancing zone; edema zone and tumor total zone. Each compartment was submitted to volumetric analysis using Horos Project software. A linear regression model was used to assess correlations between the ki-67 index and the volume of each compartment with a p-value of 0.05. Results The male/female ratio in our study was 1.7:1, at a mean age of 60.7 ± 14.6 years. Tumor predominant location was the temporal lobe with 25% of cases and cystic morphology was present in 17%. The median of Ki-67 was 40%. The average tumor compartment volume was 40 cm3 for the contrast-enhancing zone, 62 cm3for the edema zone, and 103 cm3 for the total tumor volume. A significant association between the Ki-67 index and edema zone volume (p=0.02) was found.  Conclusion Volumetric analysis of the glioblastoma edema zone by MRI allows for predicting tumor aggressiveness through correlation with the Ki-67 index.