World Health Organization Grade II Meningioma: A 10-Year Retrospective Study for Recurrence and Prognostic Factor Assessment.

BACKGROUND

We analyzed the characteristics of patients with World Health Organization (WHO) Grade II meningioma to identify factors that may influence recurrence.

MATERIALS AND METHODS

Between January 2000 and August 2015, 178 cases of WHO Grade II meningioma were operated at our institution. This population underwent a total of 224 surgical resections, and 36 patients received radiotherapy. Median follow-up was 3.6 years, and interquartile range was 1.5-6.2.

RESULTS

A total of 28 patients (16.1%) were re operated for a relapse of their Grade II meningioma. The median time between the first and the second surgery was 4.2 years [interquartile range 1.4-5.3]. Surgical recurrence-free survival at 1, 2, 5, and 10 years were: 96.9% (95% confidence interval [95% CI] 94.2-99.6; 91.7%, 95% CI 87.3-96.3; 85%, 95% CI 78.6-92; and 70.8%, 95% CI 60.1-83.5), respectively. At the end of the study, 93 patients (57.8%) had no residual tumor on the last scan. Age at diagnosis (hazard ratio [HR] 0.17, 95% CI 0.05-0.56, P < 0.001), extent of resection (HR 0.22, 95% CI 0.08-0.64, P = 0.01), and Ki-67 index (HR 0.18, 95% CI 0.06-0.56, P < 0.001) were independent factors associated with the surgical recurrence-free survival.

CONCLUSIONS

Younger patients with a lower proliferation rate and gross total resection are less likely to undergo a reintervention for WHO Grade II meningioma recurrence. Observation rather than systematic adjuvant radiotherapy may be preferred. If possible, a redo surgery may be considered in case of relapse or tumor residual progression, because radiotherapy may not decrease the surgical recurrence-free survival after complete or incomplete resection.