To evaluate the long-term outcomes of gamma knife radiosurgery (GKRS) for meningiomas involving the major dural sinuses (MIMDS).

A retrospective analysis was conducted on the clinical data of 151 patients with MIMDS who underwent gamma knife treatment from January 2006 to December 2016 at the Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. Among the 151 patients, 100 cases were primary medium and small MIMDS, and 51 cases were residual MIMDS after operation; the diameter of the lesions was less than 5 cm. Meningiomas were mainly located in the cavernous sinus (50.3%, 76/151), followed by the sagittal sinus (29.8%, 45/151), the confluence area (8.6%, 13/151), the sigmoid sinus (6.0%, 9/151) and transverse sinus (5.3%, 8/151). The median tumor volume before gamma knife treatment in 151 patients was 3.2 cm³ (0.1-48.9 cm³), the median marginal dose of gamma knife treatment was 14.5 Gy (5-42 Gy), and the median isodose curve was 50% (33%-70%). Clinical and imaging follow-ups were performed after treatment to evaluate post-treatment complications and tumor recurrence. The Kaplan-Meier survival analysis method was used to determine the progression-free survival (PFS). Through univariate and multivariate Cox regression analysis methods, we explored the related factors affecting PFS in MIMDS patients.

All patients were followed up for 70.9±33.6 months (36-172 months). Among 151 patients with MIMDS, 9 cases (6.0%) developed complications after treatment, including 3 cases of vision impairment (2.0%), 3 cases (2.0%) of radiation-induced cerebral edema, 2 cases (1.3%) of hydrocephalus, and 1 case (0.7%) of exophthalmos combined with ulcer. The overall 5-year and 10-year PFS of 151 patients after GKRS were 87.6% and 78.8%, respectively. Log-rank results showed that the PFS of <60 years old patients was significantly higher than that of patients ≥60 years old, and the PFS of patients who underwent GKRS after surgery was generally higher than that of patients who underwent GKRS alone (both P<0.05). During the follow-up period, the tumor recurred in 22 cases (14.6%). The results of multivariate Cox analysis showed that age (P=0.028) and treatment method (P=0.032) were prognostic factors for tumor recurrence in MIMDS patients.

Gamma knife is a safe and effective treatment method for small and medium-sized MIMDS and postoperative residual MIMDS. It can control tumor growth for a long time and has few complications after treatment.

Meningiomas; Treatment outcome; Follow-up studies; Gamma knife; Meningiomas involving major dural sinuses