Clinical original contribution

Radiotherapy for atypical or malignant intracranial meningioma

Recurrence rates of anaplastic meningioma (AM) are high even after a complete resection with postoperative radiotherapy.

This study aimed to evaluate predictors and treatment affecting survival of recurrent AM based on our series and a systematic literature review (SLR).

Our single-institute (SI) data enrolled patients with first recurrent AM, treated in our hospital from 2012 to 2018. We retrieved eligible cases from SLR from 1966 to 2020. Our SI data and pooled data, integrating SI and SLR data, were subject to Cox proportional hazard regression analysis.

Analysis from SI data (n = 38) showed that second recurrence-free survival (RFS) was associated with intervals (HR [hazard ratio], 0.263; P = 0.002), preoperative Karnofsky Performance Status (KPS) (HR, 0.450; P = 0.043), radiotherapy (HR, 0.395; P = 0.047), whereas overall survival (OS) was related to preoperative KPS (HR, 0.411; P = 0.037) and tumor size (HR, 3.429; P = 0.007). The pooled data (n = 60) indicated that short intervals (HR, 0.370; P = 0.002) and the use of radiotherapy (HR, 0.318; P = 0.003) improved second RFS and number of resections ≥3 (HR, 0.210; P = 0.002) and radiotherapy (HR, 0.209; P = 0.002) prolonged OS. Furthermore, the overall second RFS (P = 0.024) and OS (P = 0.031) stratified by 4 treatment protocols differed significantly.

Early managements of patients with AM, before presence of poor preoperative KPS and large tumor size, are critical for survival. For patients with recurrent AM, survival benefits could be obtained from radiotherapy and multiple resections.

We aimed to develop a radiomics model to predict the histopathological grading of meningiomas by magnetic resonance imaging (MRI) before surgery.

We recruited 131 patients with pathological diagnosis of meningiomas. All the patients had undergone MRI before surgery on a 3.0 T MRI scanner to obtain T1 fluid- attenuated inversion recovery (T1 FLAIR) images, T2-weighted images (T2WI) and T1 FLAIR with contrast enhancement (CE-T1 FLAIR) images covering the whole brain. The removing features with low variance, univariate feature selection, and least absolute shrinkage and selection operator (LASSO) were used to select radiomics features. Six classifiers were used to train the models (logistic regression (LR), k-nearest neighbor (KNN), decision tree (DT), support vector machine (SVM), random forests (RF), and XGBoost), and then 24 models were established using a random verification method to differentiate low-grade from high-grade meningiomas. The performance was assessed by receiver-operating characteristic (ROC) analysis, the f1-score, sensitivity, and specificity.

The radiomics features were significantly associated with the histopathological grading. Quantitative imaging features (n = 1409) were extracted, and nine features were selected to predict the grades of meningiomas. The best performance of the radiomics model for the degree of differentiation was obtained by SVM (area under the curve (AUC), 0.956; 95% confidence interval (CI), 0.83–1.00; sensitivity, 0.87; specificity, 0.92; f1-score, 0.90).

The radiomics models are of great value in predicting the histopathological grades of meningiomas, and have broad prospects in radiology and clinics.

Phase 2 cooperative group meningioma trial assessing the safety and efficacy of risk-adaptive management strategies. This is the initial analysis of the high-risk cohort.

High-risk patients were those with a new or recurrent World Health Organization (WHO) grade III meningioma of any resection extent, recurrent WHO grade II of any resection extent, or new WHO grade II after subtotal resection. Patients received intensity-modulated radiotherapy (IMRT) using a simultaneous integrated boost technique (60 Gy high dose and 54 Gy low dose in 30 fractions). Three-year progression-free survival (PFS) was the primary endpoint. Adverse events (AEs) were scored per NCI Common Terminology Criteria for Adverse Events version 3.

Of 57 enrolled patients, 53 received protocol treatment. Median follow-up was 4.0 years (4.8 years for living patients). Two patients withdrew without progression before year 3; for the remaining 51 patients, 3-year PFS was 58.8%. Among all 53 protocol-treated patients, 3-year PFS was 59.2%. Three-year local control was 68.9%, and overall survival was 78.6%. Of 51 patients, 1 patient (1.9%) experienced a late grade-5 necrosis-related AE. All other acute (23 of 53 patients) and late (21 of 51 patients) AEs were grades 1 to 3.

Patients with high-risk meningioma treated with IMRT (60 Gy/30) experienced 3-year PFS of 58.8%. Combined acute and late AEs were limited to grades 1 to 3, except for a single necrosis-related grade 5 event. These results support postoperative IMRT for high-risk meningioma and invite ongoing investigations to improve outcomes further.

Radiation therapy (RT) plays an important role in the management of meningioma. Surgery often remains the initial treatment of choice as it reduces mass effect and confirms the diagnosis and grade. However, RT has frequently been successful in the primary setting and is commonly employed as adjuvant therapy for incompletely resected tumors as well as for high-grade meningiomas regardless of resection extent. Some meningiomas develop in locations less amenable to resection or in patients who are poor surgical candidates, in which circumstances RT is particularly appropriate as primary treatment. Recent cooperative group studies including RTOG 0539 have better established the role of RT for meningioma. These studies suggest a role for adjuvant RT for completely resected Grade II meningioma, which was less clear historically. Ongoing clinical trials such as NRG BN 003 and ROAM will further clarify this. This chapter reviews the role of fractionated external beam RT for various grades of meningioma.