Analysis of radiotherapy in patients with intermediate- and high-risk meningiomas

This study aimed to investigate treatment outcomes in patients with intermediate- and high-risk meningioma who underwent radiotherapy (RT) and identify prognostic factors for progression-free survival (PFS). In addition, failure patterns after RT were analyzed.

We retrospectively reviewed 61 patients with intermediate- and high-risk meningiomas, categorized according to the NRG Oncology/Radiation Therapy Oncology Group 0539 trial, who underwent surgery followed by adjuvant or salvage RT.

We included 12 and 49 patients with intermediate- and high-risk meningiomas, respectively. A total of 26 cases of tumor progression and 17 deaths after RT were identified. The 5-year PFS and overall survival of the entire cohort were 55.8% and 74.2%; intermediate-risk group, 80.2% and 100%; high-risk group, 48.7% and 67.1%, respectively. The World Health Organization (WHO) grade 3 (hazard ratio [HR], 16.7; 95% confidence interval [CI], 3.0 to 92.3; p = 0.001) and recurrent tumor (HR, 41.2; 95% CI, 3.6 to 473.6; p = 0.003) were identified as adverse prognostic factors for PFS in high-risk patients. Among the 15 patients who had recurrence after conventional fractionated radiotherapy (CFRT), 13 experienced local failure (LF) and two experienced distant failure.

RT with adjuvant or salvage intent showed favorable treatment outcomes in patients with intermediate- to high-risk meningioma. WHO grade 3 histology and recurrent tumors were identified as adverse prognostic factors for PFS in high-risk patients. LF was the dominant failure pattern after CFRT, accounting for 86.7% of all recurrences. These findings underscore the need for further studies on dose-escalated RT to enhance local control in patients with these adverse features.