Gamma knife radiosurgery as primary management for intracranial meningioma identified as growing on serial imaging.

Gamma knife radiosurgery (GKRS) has emerged as a highly effective therapeutic modality for the management of intracranial meningiomas. However, the role of GKRS in treating growing meningiomas detected during active surveillance remains unclear. This study seeks to investigate the long-term outcomes of GKRS treatment for growing meningiomas. A retrospective analysis was conducted on patients who underwent GKRS as the primary treatment for growing meningiomas between 2004 and 2021. Growing meningiomas were defined as those exhibiting a > 10% increase in tumor volume (TV) compared to the previous imaging. Fifty-nine patients who received GKRS as their initial treatment were included, with a minimum follow-up period of 12 months. Comprehensive clinical, radiological, and procedural data were analyzed. Serial TV assessments were performed for all tumors before and after GKRS. Tumor progression and regression were defined as a > 10% increase or decrease in TV, respectively, compared to the pretreatment image. At a median follow-up of 41 months (range 15-197 months), TV was unchanged in 16 patients (27.1%), decreased in 41 patients (69.5%), and increased in 2 patients (3.4%). Multivariate analysis revealed that both TV (cm3) (hazard ratio [HR], 1.107; 95% confidence interval [CI], 1.002-1.222; P = .045) and volume growing rate (%/yr) (HR, 1.013; 95% CI, 1.000-1.025; P = .04) significantly correlated with tumor progression. Eleven patients (18.6%) experienced new or worsening symptoms. In multivariate analysis, factor predicting new or worsening neurological function was preexisting calcification (HR, 5.297; 95% CI, 1.328-21.124; P = .018). GKRS demonstrates a promising level of tumor control with minimal risk of neurological deterioration when applied to growing meningiomas. These findings provide compelling support for considering GKRS as a valuable therapeutic option following an initial period of active surveillance for these tumors.