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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Affiliation: | 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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