High risk of recurrence for grade II meningioma: a 10-year multicenter analysis of prognosis factors.

BACKGROUND

Atypical meningioma is a variant of meningioma with a high risk of recurrence. Gross total resection is the standard of treatment, while no consensus on optimal adjuvant management has been found.

METHODS

Between 2008 and 2018, a retrospective search identified 216 grade II meningiomas treated in six centers. Clinical, histological, and therapeutic data were analyzed to determine the prognostic factors of recurrence and survival.

RESULTS

In total, 216 patients underwent surgical resection. Among these, 122 patients (56%) underwent gross total resection, and 21% of the patients received adjuvant radiotherapy. Univariate analysis reported subtotal resection, high Ki-67, negative progesterone receptor (PR) and histological grade evolution as unfavorable prognosis factors. According to multivariate analysis, the Ki-67 proliferative index (cut-off value of 17.5%) was the only prognostic factor of recurrence (HR 1.1; 95% CI, 1.0-1.2, P=0.048). Gross total resection improved progression-free survival (PFS) (P=0.03) but without impact on overall survival (OS) (P=0.2). Median PFS and OS times were longer for patients receiving adjuvant radiotherapy than those who did not receive adjuvant radiotherapy. PFS (P=0.3) and OS (P=0.7) were associated with adjuvant RT by trend only. After a median follow-up time of 6.7 years, 99 (46%) patients relapsed. Median progression-free and OS rates were 4.5 (95% CI, 3.5-5.5) and 14.7 years (11.4-NA), respectively.

CONCLUSIONS

In this study, Ki-67 proliferative index was significantly associated with recurrence. Gross total resection significantly improved PFS without impacting OS. Adjuvant radiotherapy delayed recurrence and improved OS, but a longer follow-up time is needed to distinguish a statistically significant difference. Large prospective studies are needed to determine postoperative treatment guidelines.