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Journal of Clinical Oncology, 2005 ASCO Annual Meeting Proceedings.
Vol 23, No 16S (June 1 Supplement), 2005: 1533
© 2005 American Society of Clinical Oncology
Prognostic significance of MIB-1 labeling indices for oligodendroglial tumors
U. Abacioglu,
M. Sengoz,
E. Tezcanli,
S. Akpulat,
S. Peker and
A. Sav
Marmara Univ Hosp, Istanbul, Turkey
1533
Background: Oligodendroglial tumors (OT) are the third most common glial tumors. MIB-1 is an antibody against Ki-67 nuclear protein whose level is indicative of proliferative activity in cells within a tumor. We aimed to investigate the prognostic factors for treatment outcome in patients with OT and determine the prognostic value of MIB-1 labeling index (LI). Methods: 56 consecutive patients who received postoperative radiotherapy (RT) between April 1997 and June 2003 for a diagnosis of OT were included in the study. 32 patients (57%) presented with pure oligodendroglioma (OD) and 24 (43%) with mixed oligoastrocytoma (OA). 19 tumors (34%) were grade 2, and 37 (66%) grade 3. Male/Female ratio was 15/41 and ages ranged between 13–82 years (median 41.5). Histopathologic diagnosis was performed after gross total resection in 21, subtotal resection in 28 and stereotactic biopsy in 7 patients. Postoperative KPS scale ranged between 40 and 100 (median 90). All patients received postoperative RT to a median total dose of 60 Gy (range, 54–66 Gy). 20% of the patients received adjuvant PCV chemotherapy (CT). Results: Median PFS and OS rates for all patients were 40 months and 52 months, respectively. In univariate analysis patients with grade 2 tumors (p<0.001), OD histopathology (p=0.043), KPS>70 (p<0.001), age  45 years (p<0.001), history of seizure (p=0.017) and MIB-1 LI<2 (p=0.035) had favorable prognosis for PFS and OS. CT, gender, type of surgery, tumor location and tumor diameter did not affect prognosis. In multivariate analysis age, sex, history of seizure, grade and KPS were independent prognostic factors for PFS. Median MIB-1 LI was 2.6 (range, 0.16–54.4) for all patients; 1.0 (range, 0.2–54.4) for grade 2 tumors; and 5.5 for grade 3 tumors (range, 0.16–50). When patients were analyzed separately for OD and OA, MIB-1 LI was found to be a significant prognostic factor for OD (p=0.014), but not for OA histopathology (p=0.266). Conclusions: In OTs MIB-1 LI is demonstrated to be a significant, but not independent prognostic factor for treatment outcomes, in addition to classical prognostic factors for most brain tumors. This significance is prominent in pure ODs and may render being considered in future prospective trials.
No significant financial relationships to disclose.
Abstract presentation from the 2005 ASCO Annual Meeting
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