Treatment modalities and outcomes for asymptomatic meningiomas

The aim of this study is to investigate the outcomes of asymptomatic meningiomas (MNGs) after a variety of treatment modalities, including observation, microsurgery (MS), and gamma knife radiosurgery (GKRS).

From 1996 to 2008, 154 patients with asymptomatic MNGs were treated, and their medical records and imaging data were retrospectively analyzed. There were 121 females and 33 males with a mean age of 59.2 years (range 27-87). Treatment modalities were essentially chosen by patient preference from observation, MS, and GKRS. The mean follow-up duration was 61.2 months (range 24-157) from diagnosis.

Of our patient sample, 77 patients initially opted for observation. Tumor volume increased in 24 (31.2%) of these patients. MS or GKRS was required in nine of these patients, and the mean duration until intervention was 48.8 months (range 13-134). MS was performed as an initial treatment in eight patients without resulting in permanent neurologic deficit. No tumor recurrence occurred after surgery (mean follow-up 59.6 months; range 24-108). GKRS was performed in 69 patients. After GKRS, tumor size was stable in 57 and decreased in 12 patients, while no patient showed an increase in tumor size (mean follow-up 63.0 months; range 24-110). Transient complications developed in 27 patients (39.1%), though permanent neurologic deficit did not develop in any patient. The progression-free survival (PFS) rates at 4 and 5 years with observation were 77.2 ± 5.5% and 61.8% ± 7.7%. The difference in PFS between GKRS and observation was statistically significant (p = 0.001).

There is a substantial probability of growth of asymptomatic MNGs. GKRS can lower this possibility, but the risk of transient complications due to irradiation exists. There are no significant differences in final outcome according to initial treatment. Considering the clinical course and final outcome, both observation with regular follow-up and GKRS may be reasonable choices for asymptomatic MNGs according to preference of the patients.