The Ki-67 labeling index as a prognostic factor in Grade II oligoastrocytomas

• Published in: Journal of neurosurgery Vol. 102; no. 6; p. 1033
• Main Authors: Shaffrey, Mark E, Farace, Elana, Schiff, David, Larner, James M, Mut, Melike, Lopes, M Beatriz S
• Format: Journal Article
• Language: English
• Published: United States 01.06.2005
• Subjects: Adult; Age Distribution; Antineoplastic Agents - therapeutic use; Astrocytoma - metabolism; Astrocytoma - mortality; Astrocytoma - pathology; Astrocytoma - therapy; Biomarkers, Tumor; Brain Neoplasms - metabolism; Brain Neoplasms - mortality; Brain Neoplasms - pathology; Brain Neoplasms - therapy; Female; Humans; Ki-67 Antigen - metabolism; Male; Middle Aged; Predictive Value of Tests; Prognosis; Radiotherapy; Retrospective Studies; Survival Analysis
• ISSN: 0022-3085; 1933-0693
• DOI: 10.3171/jns.2005.102.6.1033

This study was conducted to determine whether proliferative tumor activity, as assessed using the Ki-67 immunohistochemical labeling index (LI), has prognostic utility for patients with Grade II oligoastrocytomas. The study period spans the years 1988 to 2000. In a retrospective analysis, the authors selected cases with biopsy-proven diagnoses of Grade II oligoastrocytomas on initial presentation. The authors added new patients to this group and followed all patients prospectively at the University of Virginia Neuro-Oncology Center. Twenty-three adult patients were followed for at least 1 year (median 40.3 months). Eleven patients with Grade II tumors and initial Ki-67 LIs less than 10% had a significantly longer median time to tumor progression (TTP, 51.8 months compared with 9.9 months) and a longer median survival (93.1 months compared with 16.1 months) than 12 patients with initial Ki-67 LIs of 10% or greater. Twelve patients with Grade III oligoastrocytomas had a mean TTP that was similar to the TTP of patients with Grade II tumors and high Ki-67 LIs (mean 4 months compared with 9.9 months) and duration of survival (13.3 months compared with 16.1 months). Patients with a Grade II oligoastrocytoma and a Ki-67 LI of 10% or greater have a much shorter TTP and potentially a poorer disease prognosis than expected--more similar to patients with a Grade III oligoastrocytoma. These results indicate that in the future a measure of proliferative activity should be taken into consideration along with the World Health Organization grading criteria for oligoastrocytomas.