THE NATURAL COURSE OF INCIDENTAL INTRACRANIAL MENINGIOMAS: SYSTEMATIC REVIEW AND META-ANALYSIS.

Background: With the increasing availability of radiological imaging, detection of incidental intracranial meningiomas in asymptomatic patients has increased dramatically. The best management of incidentally found meningiomas is not as clear. A systematic review and meta-analysis of the studies currently available allows for a better understanding of the natural course of asymptomatic meningiomas, a platform for more research, and a foundation on which a standardized guideline for following these tumors may be built. Methods: A systematic review of the English language literature published before October 2017 with no lower date limit was carried out. Data collected from the articles included years of the study, study location, study design, number of patients with asymptomatic meningiomas with follow-up, number of meningiomas, inclusion of NF2 patients, mean age, gender, whether tumor was defined as growing or not, tumor location, MRI characteristics, initial size of the tumors, growth rates, and outcome of follow-up. Meta-analysis of the collected data was carried out. Results: Twenty studies were identified and included in the meta-analysis (1108 patients, 1175 meningiomas). Meta-analysis results revealed an inverse relationship between age of patients and tumor growth (P<0.001). There was no significant correlation between tumor growth and gender (P=0.15). The presence of calcification was associated with significant reduced risk of growth (P<0.001). Meanwhile, growth was associated with the presence of edema (P=0.005) and T2 hyperintensity (P