Prognostic implication of clinical, radiological, and pathological features in patients with oligodendroglial tumors.

A Tortosa MD PhD^a,d, M Brell MD^b, P Teixidor MD^b, JJ Acebes MD PhD^b,d, L Caral MD^c, JM Gil MD^b, T Pujol MD^c, T Ribalta MD PhD^c,d, E Verger MD^c, S Vill, Ã

^aInstitut de Neuropatologia ICS, Bellvitge Hospital, Barcelona, , ^bCiutat Sanitària i Universitària de Bellvitge, Barcelona, , ^cHospital Clínic de Barcelona, Barcelona, , ^dUniversitat de Barcelona, Barcelona

Aim: To identify clinical, neuroradiological, pathological, and molecular factors with prognostic significance in tumors with oligodendroglial features. Methods: We analyzed 33 treated patients with histological diagnosis of oligodendroglioma or oligoastrocytoma (7 oligodendroglioma WHO grade II, 3 oligodendroglioma WHO III grade, 17 oligoastrocytoma WHO grade II and 6 oligoastrocytoma WHO grade III). Variables examined included age, sex, clinical manifestations at diagnosis (seizures, focal neurological deficit, and cognitive changes), MRI scan characteristics (diffuse, ring, and no enhancement), tumor location, extent of resection, histopathology, postoperative KPS, adjuvant radiotherapy and/or chemotherapy, proliferation index (Ki-67 expression). We also analyzed the presence of allelic loss of chromosome arms 1p and 19q in 12 patients, by assessing loss of heterozygosity (LOH) assays in tumor DNA/constitutional DNA pairs using microsatellite markers located on chromosome 1p (D1S508, D1S199 and D1S2734) and 19q (D19S219, D19S412 and D19S596). Results: Median overall survival was 41 months. LOH on chromosome 1p correlated with LOH on chromosome 19q (p=0,02). No other clinical and pathological variables were associated with these genetic alterations. Kaplan-Meier analysis showed that the absence of ring enhancement was significantly associated with longer time to recurrence (p=0.04), and a trend was also observed with respect to survival(p=0,07). No other variable was associated with tumor recurrence or overall survival. Conclusions: LOH on chromosome 1p and chromosome 19q were genetic phenomena commonly associated in oligodendroglial tumors. CT ring enhancement was identified as a predictor of survival in this series of gliomas with oligodendroglial features.

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in poster session 893 (Molecular pathology).