LAUSR

Objective The aims of this study were to investigate the long-term outcomes of primary versus postoperative Gamma Knife radiosurgery (GKRS) for benign meningiomas. Methods Three hundred and forty meningioma patients underwent GKRS were retrospectively reviewed. Patients in the postoperative GKRS group were matched to those in the primary GKRS group, in a 1:1 ratio. Results The study consisted of 122 patients, including primary ( n  = 61) and postoperative ( n  = 61) GKRS group. Thirty-four patients (27.9%) occurred radiological progression after a median follow-up of 72.5 (range, 24.2–254.5) months. The median time to radiological progression was 85.1 (range, 20.7–205.1) months. The radiological progression-free survival (PFS) was 100%, 93%, 87%, and 49%, at 1, 3, 5, and 10 years respectively. Thirty-one patients (25.4%) occurred clinical progression. The clinical PFS was 92%, 89%, 84%, and 60%, at 1, 3, 5, and 10 years. In combined group, only max diameter ≥ 50 mm was associated with radiological ( p  = 0.020) and clinical PFS (hazard ratio [HR] = 2.896, 95% confidence interval [CI] = 1.280–6.553, p  = 0.011). Twenty-five patients (20.5%) developed GKRS related adverse effects, including radiation-induced edema ( n  = 21). Non-skull base tumors (HR = 3.611, 95% CI = 1.489–8.760, p  = 0.005) and preexisting peritumoral edema (HR = 3.571, 95% CI = 1.167–10.929, p  = 0.026) were significantly related to radiation-induced edema in combined group. There was no significant difference in radiological PFS ( p  = 0.403), clinical PFS ( p  = 0.336), and GKRS related adverse effects ( p  = 0.138) between primary and postoperative GKRS groups. Conclusions Primary GKRS could provide similar radiological and clinical outcomes, as well as similar complication rate compared with postoperative GKRS. For selective benign meningioma patients (asymptomatic or mildly symptomatic tumors; unfavorable locations for surgical resection; comorbidities or an advanced age), GKRS could be an alternative primary treatment.