The role of adjuvant radiotherapy for intracranial malignant meningiomas: analysis of a nationwide database.

Purpose: This study aimed to examine the effect of postoperative radiotherapy on survival outcomes in patients with malignant meningiomas.

Methods: We identified patients with malignant meningioma diagnosed between 2007 and 2018 using the Taiwan Cancer Registry and followed them up using the death registry. Survival was compared between patients with and without adjuvant radiotherapy. The potential confounding factors evaluated in this study included age, sex, comorbidities, and the Charlson Comorbidity Index (CCI).

Results: The analysis included 204 patients; 94 (46%) received adjuvant radiotherapy. The two groups had similar sex distributions (p = 0.53), mean age (p = 0.33), histologic subtype (p = 0.13), and CCI (p = 0.62). The prognosis of malignant meningioma was poor, with a median overall survival (OS) of 2.4 years. The median OS was 3.0 years (interquartile range (IQR) [1.4-6.1], and 2.0 years (IQR [0.5-3.9]) in the radiotherapy and non-radiotherapy groups, respectively (p = 0.001). However, Kaplan-Meier curves with the log-rank test showed no significant difference in OS between the two groups (p = 0.999). Controlling for age group, sex, histologic subtype, treatment, comorbidities, and CCI, adjuvant radiotherapy did not impart a survival benefit (hazard ratio [HR] = 0.87; 95% confidence interval [CI]: 0.6‒1.26); however, only factor of higher comorbidity score (HR = 2.03, 95%CI: 1.04‒3.94) was associated with unfavorable survival.

Conclusion: This population-based retrospective analysis suggests that the role of radiotherapy remains unclear and underscores the need for randomized clinical trials to assess the usefulness of adjuvant radiotherapy in malignant meningioma.