gms | German Medical Science

Objective: Meningiomas account for 30-40% of all primary brain tumors. Mostly, meningiomas are slow growing, graded histologically as WHO°I. A small portion of meningiomas reveal a faster growths-pattern, prone to recurrence, graded as WHO°II. The course of WHO°II meningioma is variable. Although there is the possibility of postoperative radiotherapy to prevent recurrent disease, the value of prognostic factors remains hitherto unclear. The present study aims to evaluate the clinical course and histopathological pattern of WHO°II meningiomas treated in our institution to detect prognostic factors for recurrent disease.

Methods: We retrospectively reviewed the data of 64 consecutive patients who underwent surgical resection of an intracranial meningioma WHO°II between 01/2006-12/2014 in our department. Patient and tumor characteristics (sex, age, clinical symptoms, tumor localization, grade of resection), histopathological features (mitotic index, brain invasion, chordoid or clear cell subtype) and adjunctive treatment, were analyzed in sight of recurrence. Continuous data was compared by t-test for independent samples and categorical variables were analyzed using the χ 2-test or Fisher´s exact test if expected frequencies were below five. The recurrence-free rate was assessed by Kaplan-Meier estimates.

Results: A total of 55 patients (35 female, 20 male) with a mean age of 62.4 ± 13.5 years were included in the study. Headache (23.6%), seizure (21.8%) and dysarthria (14.5%) were the most common presenting signs; radiological data identified the convexity (38.2%) as the main tumor localization. Gross total tumor resection (GTR) was performed in 44 of 55 patients (80%) and histopathological examination revealed an increased mitotic index (>4 per 10 high-power fields) in 27 of 55 patients (49%). Ten of 55 patients (18.1%) received immediate, adjunctive radiotherapy. Nine patients were lost to follow-up and mean follow-up of the residual 46 patients was 44.37 ± 26.34 months. Among them, tumor recurrence was observed in 17 patients (37%) after 30.9 months (± 28.1 months). Fourteen of them (82.4%) underwent repeated surgery, which was performed 31.5 (± 29.3) months after the first surgery. The 5-year recurrence-free rate for the irradiated patients was 70% and 73.3% for the non-irradiated patients, respectively. Interestingly, during our follow-up period, statistical analysis revealed no significant association between tumor recurrence and sex, localization, GTR, adjuvant radiotherapy and histopathological features.

Conclusion: A follow-up of 4 to 5 years is insufficient to reveal the risk of recurrence of meningioma WHO°II on the basis of routinely assessed parameters. Longer follow-up periods and larger sample sizes are necessary to detect prognostic factors. The identification of biomolecular, predictive markers could be a useful approach for short-term follow-up.