Codeletions at 1p and 19q predict a lower risk of pseudoprogression in oligodendrogliomas and mixed oligoastrocytomas |
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Authors: | Andrew L Lin Jingxia Liu John Evans Eric C Leuthardt Keith M Rich Ralph G Dacey Joshua L Dowling Albert H Kim Gregory J Zipfel Robert L Grubb Jiayi Huang Clifford G Robinson Joseph R Simpson Gerald P Linette Michael R Chicoine David D Tran |
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Institution: | Department of Neurology (A.L.L., D.D.T.); Division of Biostatistics (J.L.); Department of Neurosurgery (J.E., E.C.L., K.M.R, R.G.D., J.L.D., A.H.K., G.J.Z., R.L.G., M.R.C.); Department of Radiation Oncology (J.H., C.G.R., J.R.S.); and Department of Medicine (G.P.L.), Washington University in St. Louis School of Medicine, Saint Louis, Missouri |
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Abstract: | BackgroundPseudoprogression (PsP) occurs at a higher rate in glioblastoma multiforme with a methylated MGMT promoter—a subset with increased sensitivity to chemoradiotherapy and better overall prognosis. In oligodendroglioma (OG) and oligoastrocytoma (OA), presence of 1p/19q codeletions is highly predictive of response to treatment and is often associated with the methylated MGMT promoter; hence, this study queries whether the presence of 1p/19q codeletions in OG/OA correlates with a higher rate of PsP following therapy.MethodsA retrospective analysis was performed on all OG/OA in a database of patients with brain tumors who underwent resection of their tumor since 1998. Eighty-eight cases (37 with and 51 without 1p/19q codeletions) met inclusion criteria, and their patient data were analyzed to determine whether the presence of 1p/19q codeletions was associated with PsP and survival.ResultsOG/OA (World Health Organization grades II and III) with 1p/19q codeletions had a significantly improved survival (P = .041). Multivariate analysis found that PsP occurred less frequently in OG/OA with 1p/19q codeletions compared with tumors without codeletions (odds ratio, 0.047; 95% confidence interval, 0.005–0.426; P = .0066). The rate of PsP was 19% for the entire cohort, 31% for tumors without codeletions, and 3% for tumors with codeletions. When early posttreatment contrast enhancement developed in tumors with 1p/19q codeletions, it occurred exclusively in tumors that were histologically OA and not OG.ConclusionCodeletions of 1p/19q are a marker of good prognosis but are unexpectedly associated with a lower likelihood of PsP. PsP does not correlate with sensitivity to treatment and improved survival in OG/OA. |
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Keywords: | oligodendroglioma oligoastrocytoma pseudoprogression 1p/19q codeletions p53 |
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