MATERIAL and METHODS: Data obtained from 83 patients who underwent surgery and histopathologically diagnosed with atypical meningioma at a single institution between January 2009 and June 2019 were retrospectively reviewed. Then, the patients were divided into two groups: the surgery-only (n=43) and surgery + adjuvant radiotherapy (n = 40) groups.

RESULTS: The mean age of the patients was 53.5 ± 14.6 years. Among them, 51 (61.4%) were female and 32 (38.6%) were male. The recurrence rates were 30.2% (n=13) in the surgery-only group and 17.5% (n=7) in the surgery + adjuvant radiotherapy group. A statistically significant decrease in the recurrence rate was observed after adjuvant radiotherapy application (p=0.046). Moreover, adjuvant radiotherapy significantly increased progression-free survival (p=0.042). Peritumoral edema, sinus invasion, brain invasion, subtotal tumor resection, and complications were significant predictors of tumor recurrence, and the main risk factors for the recurrence of atypical meningiomas were brain invasion (p=0.019) and subtotal tumor resection (p=0.006). Progression-free survival and overall survival of the study group were 45.50 ± 27.56 and 56.69 ± 28.17 months, respectively. The parameters examined in the study, except for tumor recurrence, did not show a statistically significant influence on overall survival.

CONCLUSION: This study revealed that the important prognostic factors for tumor recurrence are subtotal tumor resection and brain invasion. Moreover, adjuvant radiotherapy in addition to surgical resection reduces the recurrence rate of atypical meningiomas and improves progression-free survival of the patients. However, adjuvant radiotherapy did not show a significant influence on overall survival. Keywords : Atypical meningioma, Radiotherapy, Recurrence, Surgical resection, Brain invasion