Radiologic Response and Disease Control of Recurrent Intracranial Meningiomas Treated With Reirradiation

Purpose: To evaluate the clinical outcomes of reirradiation of recurrent meningiomas and factors related to patient selection and treatment modality. Methods and Materials: Recurrent meningioma patients who failed prior stereotactic radiosurgery (SRS) or fractionated external beam radiation therapy (EBRT) received reirradiation using either SRS or EBRT. Complete response (CR), partial response (PR), and progression after reirradiation were evaluated using the MacDonald criteria. Local control (LC), progression-free survival (PFS), and overall survival (OS) after reirradiation were analyzed using the Kaplan-Meier method. Logistic and Cox regression analyses were performed to identify factors associated with reirradiation modality and PFS, respectively. Results: Forty-three patients (14 grade 1/unknown, 29 grade 2/3) were reirradiated with SRS (67%) or EBRT (33%). Median time from initial SRS/EBRT to reirradiation was 60 months (range, 7.5-202); median tumor volume at the time of reirradiation was 4.8 cm ³ (range, 0.14-64). After a median radiologic follow-up of 19.4 months, the response rate (CR + PR) was 8% for grade 1 and 20% for grade 2/3 meningiomas. After 2 years, LC was 78%, PFS was 63%, and OS was 80%. Larger tumor volume and prior SRS were associated with reirradiation using EBRT. Reirradiated grade 2/3 meningiomas had significantly worse PFS than grade 1 (2-year PFS: 50% vs 92%, respectively; P =.02) but not LC (P =.11) or OS (P =.39). On multivariable analysis, worse PFS was significantly associated with grade 2/3 histology (hazard ratio, 3.92; 95% confidence interval, 1.33-11.6) as well as worse Karnofsky Performance Scale score but not reirradiation dose, volume, and modality. Grades 3 to 4 radiation necrosis developed in 4 patients (10%). Conclusions: Reirradiation of recurrent meningiomas appears to be feasible with promising clinical outcomes and an acceptable toxicity profile.