Tihan Tarik, Zhou Tianni, Holmes Emi, Burger Peter C, Ozuysal Sema, Rushing Elisabeth J
Department of Pathology, University of California, San Francisco, CA 94143-0102, USA.
Mod Pathol. 2008 Feb;21(2):165-77. doi: 10.1038/modpathol.3800999. Epub 2007 Dec 14.
We performed a retrospective analysis of 96 pediatric posterior fossa ependymomas in order to determine the prognostic value of histological grade based on the current WHO grading scheme. The patients were selected among Children's Oncology Group (previously Pediatric Oncology Group-POG) patients enrolled in clinical trials, and on the basis of central pathology review, location, and age. We excluded entities such as sub-ependymoma, myxopapillary, or clear-cell ependymoma, after a consensus diagnosis by three neuropathologists. A total of 66 males and 30 females with a median age of 48 months were identified. The group was analyzed to determine the effects of histological grade, age, gender, and extent of resection on event-free and overall survival. Our results showed that extent of resection, age, and histological grade were independent prognostic variables for event-free survival. The relative risk for extent of resection and histological grade was calculated as 3.59 (P<0.001) and 3.58 (P<0.001), respectively. Overall survival significantly correlated with extent of resection and age, but not with histological grade. We compared our results with peer-reviewed publications on pediatric intracranial ependymomas in the English language between 1990 and 2005. Selection criteria identified 32 manuscripts involving 1444 patients. Extent of resection was a significant factor in 21, age in 12, and histological grading in nine of these studies. Other factors reported to be significant by more than one study included tumor location and radiation treatment. Our findings suggest that histological grade (WHO Grade II vs III) is an independent prognostic indicator for event-free survival, but may not be so for overall survival in pediatric posterior fossa ependymomas. We believe that an accurate assessment of the prognostic value of histological grade depends on the selection of a well-characterized clinical cohort of sufficient size, and the inclusion of relevant histological criteria as outlined in the WHO classification scheme.
我们对96例小儿后颅窝室管膜瘤进行了回顾性分析，以确定基于当前世界卫生组织（WHO）分级方案的组织学分级的预后价值。这些患者选自参加临床试验的儿童肿瘤研究组（以前的儿童肿瘤研究组 - POG）患者，并基于中心病理复查、肿瘤位置和年龄进行选择。在三位神经病理学家达成共识诊断后，我们排除了室管膜下瘤、黏液乳头型或透明细胞型室管膜瘤等实体瘤。共确定了66例男性和30例女性，中位年龄为48个月。对该组进行分析，以确定组织学分级、年龄、性别和切除范围对无事件生存期和总生存期的影响。我们的结果表明，切除范围、年龄和组织学分级是无事件生存期的独立预后变量。切除范围和组织学分级的相对风险分别计算为3.59（P<0.001）和3.58（P<0.001）。总生存期与切除范围和年龄显著相关，但与组织学分级无关。我们将我们的结果与1990年至2005年间以英文发表的关于小儿颅内室管膜瘤的同行评审出版物进行了比较。选择标准确定了32篇涉及1444例患者的手稿。在这些研究中，切除范围在21项研究中是一个重要因素，年龄在12项研究中是重要因素，组织学分级在9项研究中是重要因素。多项研究报告的其他重要因素包括肿瘤位置和放射治疗。我们的研究结果表明，组织学分级（WHO二级与三级）是小儿后颅窝室管膜瘤无事件生存期的独立预后指标，但对总生存期可能并非如此。我们认为，对组织学分级预后价值的准确评估取决于选择一个特征明确、规模足够大的临床队列，并纳入WHO分类方案中概述的相关组织学标准。
