Long-term Follow-up Study of Supratentorial Diffuse Astrocytoma : Risk Factors for Malignant Transformation(<SPECIAL ISSUE>Treatment of Diffuse Astrocytoma Grade 2)

Abstract

Diffuse astrocytoma (WHO grade 2) is a diverse tumor category, which has a tendency to become anaplastic astrocytoma and glioblastoma with marked individual variation. From the results of 85 cases of diffuse astrocytomas treated in the Kyoto University Hospital (1978-2005), the median overall survival time and progression free survival time were 15 years and 8 years, respectively. Malignant progression was the most significant factor correlated to overall survival and progression-free survival. In addition, significantly prognostic factors for early malignant progression were single mitosis and MIB-1 staining index (>3.5%) in surgical specimens taken by the initial surgery. Such high-risk cases of diffuse astrocytomas should be differentiated from ordinary ones in both their treatment strategies and follow-up schedules.