Grading of diffusely infiltrating astrocytomas by quantitative histopathology, cell proliferation and image cytometric DNA analysis : Comparison of 133 tumours in the context of the WHO 1979 and WHO 1993 grading schemes

• Published in: Neuropathology and applied neurobiology Vol. 26; no. 4; pp. 319 - 331
• Main Authors: SALLINEN, P. K, SALLINEN, S.-L, HELEN, P. T, RANTALA, I. S, RAUTIAINEN, E, HELIN, H. J, KALIMO, H, HAAPASALO, H. K
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Science 01.08.2000
• Subjects: Astrocytoma - chemistry; Astrocytoma - classification; Astrocytoma - pathology; Biological and medical sciences; Brain Neoplasms - chemistry; Brain Neoplasms - classification; Brain Neoplasms - pathology; Cell Division; Cell Nucleus - pathology; Decision Support Techniques; DNA, Neoplasm - analysis; Endothelium, Vascular - pathology; Female; Glioblastoma - chemistry; Glioblastoma - classification; Glioblastoma - pathology; Humans; Image Cytometry - methods; Immunohistochemistry; Male; Medical sciences; Middle Aged; Necrosis; Neoplasm Invasiveness; Neurology; Predictive Value of Tests; Prognosis; ROC Curve; Sensitivity and Specificity; Survival Analysis; Survival Rate; Tumors of the nervous system. Phacomatoses; Histological grading; Human; Cell proliferation; Nervous system diseases; Prognosis; Tumorous infiltration; Malignant tumor; Malignant glioma; Cytometry; Image analysis; Histopathology; Malignant astrocytoma; DNA; Central nervous system disease; Quantitative analysis
• ISSN: 0305-1846; 1365-2990
• DOI: 10.1046/j.1365-2990.2000.00240.x

The aim of the study was to evaluate the applicability of quantitative histopathology as an aid for grading diffusely infiltrating astrocytomas. Primary astrocytomas were analysed for parameters (mean nuclear size, mitosis count, area fraction of endothelial cells and tumour necrosis, area fraction of nuclei, and Ki-67 (MIB-1) labelling index), which are closely related to the World Health Organization (WHO) 1979 and WHO 1993 grading criteria. All estimates correlated with the WHO histopathological grade and patient outcome. According to the receiver-operating characteristics curve, the presence of tumour necrosis and mitosis count (cut-off at 3 mitoses/mm2 of neoplastic tissue) showed the best sensitivity and specificity in separating patients with different survival. The multivariate survival analyses confirmed this result. A decision-tree model was constructed based on these two variables: twig I with less than 3 mitoses/mm2, twig II with equal or more than 3 mitoses/mm2 but no necrosis, and twig III with tumour necrosis. This model was found to be more strongly associated with survival than the WHO 1979 or WHO 1993 grading schemes. Low-malignancy astrocytomas (WHO grade II or twig I tumours) could be further divided into two prognostic categories by the image cytometric DNA analysis. The results put an emphasis on astrocytoma grading on mitosis counts (grade II vs. III) and tumour necrosis (grade III vs. IV). To standardize the sampling for mitosis counting, it is suggested that a parallel Ki-67 immunostaining be used for the identification of the most proliferative areas.