PURPOSE For meningiomas, the 2016 revision of the WHO classification introduced brain invasion per se as a sufficient condition to classify as grade II. We analyzed whether meningiomas previously graded as WHO grade I differ in prognosis depending on the presence of microscopic brain invasion. METHODS A consecutive series of patients with intracranial meningioma WHO grade I (± brain invasion) at two neurosurgical departments was analyzed retrospectively. Cox regression models on progression-free survival (PFS) and Kaplan-Meier survival estimates were performed. RESULTS 875 adult patients were included. Histological diagnosis of brain invasion was confirmed in 28 patients. Median follow-up was 73 months. In univariate and multivariate models, gross total resection gained favorable prognostic influence for PFS (p < 0.001, HR: 0.237, CI 0.170-0.382). 170 patients with the brain/meningioma interface present in histopathological specimen were separately analyzed as a subgroup. Importantly, presence of brain invasion did not reach significance for PFS, even in the subgroup with available specimen of brain/meningioma interface (p = 0.787, HR: 0.852, CI 0.268-2.710 and p = 0.811, HR: 0.848, CI 0.222-3.246, respectively). Patients with and without brain invasion did not differ in terms of age, tumor location and extent of resection, but were more likely to receive radiotherapy (p = 0.03) of tumor remnants. However, subgroup analysis of non-irradiated tumors revealed no prognostic influence of brain invasion (p = 0.749, HR: 0.772, CI 0.158-3.767). CONCLUSIONS In this bi-institutional series, brain invasion was frequent among meningiomas WHO grade I when brain/meningioma interface was available for histology (16.5%). However, brain invasion did not impact early recurrence.

中文翻译：

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先前归类为WHO WHO I级的脑膜瘤的微观脑部浸润与患者预后无关。

目的对于脑膜瘤，2016年世卫组织分类修订版引入了脑浸润本身，这是分类为II级的充分条件。我们分析了先前分级为WHO WHO I级的脑膜瘤在预后方面是否有所不同，这取决于存在微观脑部侵袭。方法回顾性分析了两个神经外科部门的一系列颅内脑膜瘤患者的WHO WHO I级（±脑浸润）。进行了无进展生存期（PFS）和Kaplan-Meier生存估计的Cox回归模型。结果纳入了875名成年患者。组织学诊断为脑侵犯的确诊28例。中位随访时间为73个月。在单变量和多变量模型中，大体全切除术对PFS有良好的预后影响（p <0.001，HR：0.237，CI 0.170-0。382）。将170例组织病理学标本中存在脑/脑膜瘤界面的患者作为一个亚组进行单独分析。重要的是，即使在有可用脑/脑膜瘤界面标本的亚组中，脑浸润对PFS也没有意义（p = 0.787，HR：0.852，CI 0.268-2.710，p = 0.811，HR：0.848，CI 0.222-分别为3.246）。有无脑浸润的患者在年龄，肿瘤位置和切除范围方面无差异，但更有可能接受放疗（p = 0.03）的肿瘤残留物。然而，未照射肿瘤的亚组分析未发现脑部侵袭的预后影响（p = 0.749，HR：0.772，CI 0.158-3.767）。结论在这个双机构系列中，当脑/脑膜瘤接口可用于组织学检查时，世卫组织I级脑膜瘤中脑部侵袭频繁（16.5％）。但是，脑部入侵并未影响早期复发。