Alterations of chromosome arms 1p and 19q as predictors of survival in oligodendrogliomas, astrocytomas, and mixed oligoastrocytomas

Purpose: A recent report suggests that alterations of chromosome arms 1p an d 19q are associated with chemotherapeutic response and overall survival in anaplastic oligodendroglioma patients treated with procarbazine, lomustine , and vincristine chemotherapy. We set out to further clarify the diagnosti c and prognostic implications of these alterations in a broader set of diff use gliomas, including astrocytic neoplasms and low-grade oligodendroglioma s. Patients and Methods: Fluorescence in situ hybridization (FISH) signals fro m DNA probes mapping to 1p and 19q common deletion regions were enumerated in 162 diffuse gliomas (79 astrocytomas, 52 oligodendrogliomas, and 31 mixe d oligoastrocytomas), collected as part of an ongoing prospective investiga tion of CNS tumors. Results: The oligodendroglial phenotype was highly associated with loss of 1p (P = .0002), loss of 19q (P < .0001), and combined loss of Ip and 19q (P < .0001). univariate predictor of prolonged overall survival among patient s with pure oligodendroglioma (log-rank, P = .03) and remained a significan t predictor after adjusting for the effects of patient age and tumor grade (P < .01). This favorable association wets not evident in patients with ast rocytoma or mixed oligoastrocytoma. Conclusion: Combined loss of 1p and 19q is a statistically significant pred ictor of prolonged survival in patients with pure oligodendroglioma, indepe ndent of tumor grade. Given the lack of this association in patients with a strocytic neoplasms and the previously demonstrated chemosensitivity of oli godendrogliomas, a combined approach of histologic and genotypic assessment could potentially improve existing strategies for patient stratification a nd management. J Clin Oncol 18:636-645. (C) 2000 by American Society of Cli nical Oncology.