The authors undertook a follow-up study of 286 patients who underwent surgical treatment for intracranial meningioma between 1973 and 1994, in order to analyse clinical, radiological, topographic, histopathological and therapeutic factors significantly influencing tumour recurrence. All patients were followed by using either computed tomography (CT) or magnetic resonance from 3 months to 17 years since first surgery (mean follow-up: 4.1 years). Forty-four (15.4%) recurrences were detected during this time period. Overall recurrence rates were 14%, 37% and 61% at 5, 10 and 15 years, respectively. Factors significantly associated with tumour relapse in bivariate analysis were: tumour location at petroclival and parasagittal (middle third) regions, incomplete surgical resection (assessed by Simpson's classification), atypical and malignant histological types (WHO classification), presence of nucleolar prominence, presence of more than 2 mitosis per 10 high-power fields, and heterogeneous tumour contrast enhancement on the CT scan. The multivariate analysis using the Cox's proportional hazards model identified the following risk factors for recurrence: incomplete surgical resection (Relative risk: 2.2; 95% Confidence interval: 1.33-3.64), non conventional histological type (RR: 2.13; 95%CI: 1-4.53), heterogeneous contrast enhancement on the CT scan (RR: 2.25; 95%CI: 1.1-4.72) and presence of more than 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.
