Larger Meningioma Size at Presentation is Associated with Higher Tumor Grade

Background: Meningiomas are often considered benign tumors, however, atypical and malignant meningiomas can be aggressive, recur, and cause significant morbidity. Currently, it is unknown whether there is a relationship between meningioma size at presentation and tumor grade. If there were a relationship between size at presentation and tumor grade, it would be informative and useful for patients as they consider treatment options for their tumors.

Objective: To investigate the relationship between tumor size at presentation and tumor grade in a large single-center population of patients undergoing meningioma resection.

Methods: A retrospective chart review of patients undergoing meningioma resection at the author’s institution (1985–2015) was performed. Cases were screened for those with information about tumor size from radiology reports as well as tumor grade from pathology reports. WHO grade was based on the contemporary grading scale at the time of surgery. We excluded WHO Grade III tumors. The largest tumor dimension was used as a surrogate for tumor size. Logistic regression and receiver operator curves were constructed to evaluate the relationship between tumor size at presentation and tumor grade.

Results: We identified 1135 patients who met the inclusion criteria. Of these, 924 (81%) were WHO Grade I, and 211 (19%) were WHO Grade II. Chi square test identified a significant relationship between tumor size and tumor grade, with larger tumor sizes being more likely to be WHO Grade II (p < 0.001). A receiver operator curve was constructed and identified a cut off for significance at 4.5 cm (AUC: 0.61495). Tumors less than 2.5 cm had a 12.5% likelihood of being WHO Grade I. Compared with tumors less than 2.5, increasing size resulted in increased odds of being WHO Grade II as follows: 2.5–4.5 cm (OR 1.12, 95% CI: 0.74–1.75), 4.6–6.5 cm (OR 2.10, 95% CI: 1.36–3.28), and >6.5 cm (OR 4.06, 95% CI: 2.28–7.24).

Conclusions: Meningioma patients with tumor size larger than 4.5 cm have a significantly increased risk for being WHO grade II, which is relevant and informative when counseling patients about the management of these tumors.