Risk factors predicting recurrence in patients operated on for intracranial meningioma. A multivariate analysis

The authors undertook a follow-up study of 286 patients who underwent surgi cal treatment for intracranial meningioma between 1973 and 1994, in order t o analyse clinical, radiological, topographic, histopathological and therap eutic factors significantly influencing tumour recurrence. All patients were followed by using either computed tomography (CT) or magn etic resonance from 3 months to 17 years since first surgery (mean follow-u p: 4.1 years). Forty-four (15.4%) recurrences were detected during this tim e period. Overall recurrence rates were 14%, 37% and 61% at 5, 10 and 15 ye ars, respectively. Factors significantly associated with tumour relapse in bivariate analysis were: tumour location at petroclival and parasagittal (middle third) region s, incomplete surgical resection (assessed by Simpson's classification), at ypical and malignant histological types (WHO classification), presence of n ucleolar prominence, presence of more than 2 mitosis per 10 high-power fiel ds, and heterogeneous tumour contrast enhancement on the CT scan. The multivariate analysis using the Cox's proportional hazards model identi fied the following risk factors for recurrence: incomplete surgical resecti on (Relative risk: 2.2; 95% Confidence interval: 1.33-3.64), non convention al histological type (RR: 2.13; 95%CI: 1-4.53), heterogeneous contrast enha ncement on the CT scan (RR: 2.25; 95%CI: 1.1-4.72) and presence of more tha n 2 mitosis per 10 high-power fields (RR: 2.28; 95%CI: 0.99-5.27). Patients without any of these features showed low recurrence rates (4% and 18% at 5 and 10 years), and thus, they need less clinical and radiological controls through the follow-up than patients with some of these risk factors.