BackgroundThe treatment strategy for patients with an asymptomatic meningioma is still controversial. Key to an optimal decision is a careful evaluation of the growth possibilities of the meningioma by taking the patient's clinicoradiologic factors into consideration. However, previous studies have disagreed about the risk factors relating to tumor growth. MethodsA comprehensive search of PubMed, Embase, and the ISI Web of Knowledge was performed. Using a meta-analysis with nine subsidiary studies including 777 patients, we analyzed the correlation of the growth pattern of meningioma with patient gender, tumor location, tumor calcification, magnetic resonance imaging (MRI) T2 signal intensity, and peritumoral brain edema. ResultsThe growth rate of meningioma was negatively correlated with tumor calcification (odds ratio [OR]: 0.23; 95% confidence interval (CI), 0.11-0.46; p<0.001) but positively associated with MRI T2 signal intensity (OR: 2.75; 95% CI, 1.75-4.33; p<0.001). No correlations were found between tumor growth and other factors such as gender (OR: 1.29; 95% CI, 0.84-1.99; p=0.24), skull base location (OR: 0.80; 95% CI, 0.25-2.58; p=0.70), and peritumoral brain edema (OR: 1.24; 95% CI, 0.29-5.27; p=0.77). ConclusionsTwo factors, tumor calcification and low MRI T2 signal intensity, indicate the possibility of a slow growth meningioma. In such cases of asymptomatic meningioma, a follow-up strategy can be preferentially considered.