BACKGROUND Meningiomas are the most common tumors occurring in the central nervous system, with variable recurrence rates depending on World Health Organization grading. Atypical (Grade II) meningioma has a higher rate of recurrence than benign (Grade I) meningioma. The efficacy of adjuvant radiotherapy (RT) to improve tumor control has been questioned. OBJECTIVE To investigate clinical and histopathological predictors of tumor recurrence and radio-resistance in atypical meningiomas. METHODS This cohort study retrospectively reviewed all patients in St. Michael's Hospital CNS tumor patient database who underwent surgical resection of a Grade II meningioma from 1995 to 2015. Cases with neurofibromatosis type II, multiple satellite tumors, spinal cord meningioma, radiation-induced meningioma, and perioperative death were excluded. Patient demographics, neuropathological diagnosis, tumor location, extent of resection, radiation therapy, and time to recurrence or progression were recorded. Cox univariate regression and Kaplan-Meier survival analysis were employed to identify risk factors for recurrence and radio-resistance. RESULTS Among 181 patients, the combination of necrosis and brain invasion was associated with an increased recurrence risk (hazard ratio [HR] = 4.560, P = .001) and the lowest progression-free survival (PFS) relative to other pathological predictors. This trend was maintained after gross total resection (GTR, P = .001). RT was associated with decreased PFS (P = .001), even in patients who received GTR (P = .001). CONCLUSION The combination of necrosis and brain invasion is a strong predictor of tumor recurrence and radio-resistance in meningioma, regardless of EOR or adjuvant RT. Our findings question the sensibility of brain invasion as an absolute criterion for Grade II status.

中文翻译：

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坏死和脑浸润预测非典型脑膜瘤的放射抗性和肿瘤复发：一项回顾性队列研究

背景脑膜瘤是发生在中枢神经系统中最常见的肿瘤，其复发率取决于世界卫生组织的分级。非典型（II 级）脑膜瘤的复发率高于良性（I 级）脑膜瘤。辅助放疗 (RT) 改善肿瘤控制的功效受到质疑。目的探讨非典型脑膜瘤肿瘤复发和放射抗性的临床和组织病理学预测因素。方法 本队列研究回顾性地回顾了圣迈克尔医院 CNS 肿瘤患者数据库中 1995 年至 2015 年接受手术切除 II 级脑膜瘤的所有患者。 II 型神经纤维瘤病、多发卫星肿瘤、脊髓脑膜瘤、放射诱发的脑膜瘤、和围手术期死亡被排除在外。记录患者人口统计学、神经病理学诊断、肿瘤位置、切除范围、放射治疗和复发或进展时间。采用 Cox 单变量回归和 Kaplan-Meier 生存分析来确定复发和放射抗性的危险因素。结果 在 181 名患者中，与其他病理预测因素相比，坏死和脑浸润的组合与复发风险增加（风险比 [HR] = 4.560，P = .001）和最低无进展生存期 (PFS) 相关。这种趋势在大体全切除后得以维持（GTR，P = .001）。放疗与 PFS 降低相关 (P = .001)，即使在接受 GTR 的患者中也是如此 (P = .001)。结论 坏死和脑浸润的结合是脑膜瘤肿瘤复发和放射抗性的强预测因子，无论 EOR 或辅助 RT。我们的研究结果质疑大脑入侵的敏感性作为 II 级状态的绝对标准。