Mittler M A, Walters B C, Stopa E G
Department of Neurosurgery, Rhode Island Hospital, Brown University, Providence, USA.
J Neurosurg. 1996 Dec;85(6):1091-4. doi: 10.3171/jns.1996.85.6.1091.
This study provides an objective assessment of the reliability of histological grading of astrocytoma specimens obtained using stereotactic biopsy. Pathological diagnosis of brain tumors provides an index of disease severity and guides clinical practice in their treatment. It also functions as the gold standard in assessing the validity of diagnostic tests such as magnetic resonance imaging. Often diagnoses are made from biopsy material obtained using stereotactic technique. The current study was designed to evaluate this gold standard with regard to interobserver and intraobserver variability. Four certified neuropathologists from academic centers in the United States and Canada were asked to grade 30 brain biopsy specimens obtained stereotactically in patients with astrocytomas. Intraobserver agreement was analyzed in individual observers by comparing their first and second readings, separated by 5 to 14 weeks. Interobserver data were analyzed by comparing initial readings across all observers for individual diagnoses. Kappa analysis was used to measure agreement beyond chance. Intraobserver agreement was 74.73% for glioblastomas multiforme, 51.43% for anaplastic astrocytomas, and 65.22% for low-grade astrocytomas. The most common disagreements were between anaplastic astrocytomas and glioblastomas multiforme, followed by disagreements between anaplastic and low-grade astrocytomas. Interobserver agreement on initial readings was 62.41% (kappa 0.39) for glioblastomas, 36.04% (kappa 0.06) for anaplastic astrocytomas, and 57.14% (kappa 0.48) for low-grade astrocytomas. A significantly greater degree of reliability was seen in histopathological diagnoses of low- or high-grade astrocytomas than in those of intermediate-grade astrocytomas. Therefore, the highest variability occurs at the point of clinical decision making--namely, intermediate-grade tumors that may or may not be selected to receive adjuvant therapy. This considerable variability is an issue that needs to be recognized and further addressed by analysis of current and proposed astrocytoma grading schemes.
本研究对采用立体定向活检获取的星形细胞瘤标本组织学分级的可靠性进行了客观评估。脑肿瘤的病理诊断提供了疾病严重程度的指标，并指导其治疗的临床实践。它还作为评估诸如磁共振成像等诊断测试有效性的金标准。通常诊断是基于使用立体定向技术获取的活检材料。本研究旨在评估这一金标准在观察者间和观察者内变异性方面的情况。邀请了来自美国和加拿大学术中心的四位具有资质的神经病理学家对30例通过立体定向获取的星形细胞瘤患者的脑活检标本进行分级。通过比较每位观察者间隔5至14周的首次和第二次读数来分析观察者内一致性。通过比较所有观察者对各个诊断的初始读数来分析观察者间数据。使用kappa分析来衡量超出偶然的一致性。多形性胶质母细胞瘤的观察者内一致性为74.73%，间变性星形细胞瘤为51.43%，低级别星形细胞瘤为65.22%。最常见的分歧存在于间变性星形细胞瘤和多形性胶质母细胞瘤之间，其次是间变性星形细胞瘤和低级别星形细胞瘤之间。胶质母细胞瘤初始读数的观察者间一致性为62.41%（kappa值为0.39），间变性星形细胞瘤为36.04%（kappa值为0.06），低级别星形细胞瘤为57.14%（kappa值为0.48）。在低级别或高级别星形细胞瘤的组织病理学诊断中观察到的可靠性程度明显高于中间级别星形细胞瘤。因此，最高的变异性出现在临床决策点——即可能选择或不选择接受辅助治疗的中间级别肿瘤。这种相当大的变异性是一个需要通过分析当前和提议的星形细胞瘤分级方案来认识并进一步解决的问题。
