Predictor factors for recurrence in atypical meningiomas.

Background and objectives: Atypical meningiomas (AMs), World Health Organization (WHO) grade 2, are a group of tumors with uneven and unpredictable clinical behavior. Our aim was to analyze possible tumor recurrence predictors, and to identify factors that improve progression-free survival (PFS).

Patients, materials and methods: Our retrospective study included 81 patients followed up in the Prof. Dr. Nicolae Oblu Emergency Clinical Hospital, Iaşi, Romania, between 1 January 2010 and 31 December 2020. The histopathological specimens were reviewed according to the WHO 2021 criteria. Analyses included clinical, imaging, pathological and surgical factors.

Results: The tumor recurred in 53.1% of the 81 cases within 60 months of surgery. Tumor location (p<0.000), tumor volume (p<0.010), extent of surgical resection (p<0.000) and dural sinus invasion (p<0.001) were predictive factors of recurrence. Gross total resection (Simpson grade I and II) was achieved in 59.2% of patients. Patients with the tumors located in the brain convexity and volume <26.4 cm³ had better survival rates up to recurrence. PFS showed a significant relationship between Simpson grade I-III and biopsy (p<0.000) and was statistically influenced by tumor volume and location, and dural sinus invasion.

Conclusions: AMs are a heterogeneous group of tumors, and we identified posterior fossa location, volume ≥26.4 cm³, Simpson grade III and IV resection and dural sinus invasion as predictive factors for relapse and a shorter PFS. Whereas certain characteristics provide some prognostic value, future molecular characterizations of AMs are necessary, which will support the clinical decision-making process.