Outcome of untreated meningiomas.

BACKGROUND: Nowadays meningiomas are frequently detected incidentally. Their natural history has not yet been established because it is difficult to predict the growth pattern. Therefore, the management, after the radiological diagnosis, is still controversial.
OBJECTIVES: To evaluate the clinical outcome and growth rate of conservatively treated meningiomas at our tertiary center, identify prognostic factors of tumor growth, and suggest guidelines based on the available data and our experience.
METHODS: We reviewed the clinical records of 56 patients with 63 untreated meningiomas. Most were diagniosed incidentally. Clinical features and imaging findings at diagnosis and during follow-up were compared between growing and non-growing tumors. Potential patient- and tumor-related predictive factors for growth were analyzed.
RESULTS: The study group included 46 women (52 meningiomas) and 10 men (11 meningiomas) aged 39-83 years. Mean tumor size was 18 +/- 11 mm (range 3-70 mm) at diagnosis and 22 +/- 11 mm (range 8-70 mm) at last follow-up; mean follow-up time was 65 +/- 34 months (range 15-152 months). During follow-up 24 tumors (38%) grew ata rate of 4 mm per year; none became symptomatic. Only two prognostic factors were statistically significantly associated with low growth rate: older age and tumor calcifications.
CONCLUSIONS: Given our finding of a low growth incidence of meningiomas in the elderly, we support conservative management in patients aged 70 years or older. Calcifications into the meningioma are also indicative of slow growth, suggesting a conservative strategy. Surgery is recommended in younger patients in whom tumor growth occurs more often and a longer follow-up is necessary.