Clinico-pathologic predictors of dismal course in atypical meningiomas: a retrospective single-centre analysis.

Background: Despite continuous refinement of the WHO Classification for meningiomas, the biological behavior of atypical meningiomas remains difficult to predict on the basis of this grading system alone. The aim of this study was to investigate the prognostic significance of clinical and radiological parameters in a series of atypical meningioma with long follow-up of minimum 5 years.

Methods: Of 1675 meningiomas treated at the Medical University Vienna (Austria) between 1993 and 2015, 179 were atypical meningioma. Of those, 93 patients were identified with follow-up of ≥5 years. Patients were grouped by recurrence and evaluated for overall and progression free survival as well as potential prognostic parameters such as age, gender, tumor size and location, edema, irregular surface, contrast enhancement, bone invasion and hyperostosis, necrosis, EOR and MIB-1.

Results: From 42 (45%) patients in group recurrent and 51 (55%) patients in group non-recurrent, seven independent factors were associated with decreased progression-free survival in univariate analysis: size ≥5 cm, age ≥60 years, male gender, subtotal resection, irregular surface, and necrosis on magnetic resonance imaging, and MIB-1≥6%. In multivariable analysis, only larger size, older age, necrosis and higher MIB-1 remained independent prognostic risk factors for recurrence of atypical meningioma.

Conclusions: We identified larger size, older age, presence of necrosis on magnetic resonance imaging, and higher MIB-1, as detrimental parameters for recurrence of atypical meningioma. Until molecular profiling of atypical meningioma becomes routinely available, these parameters may aid the clinician in decision making about surveillance intervals and adjuvant radiation treatment.