Short-term survivors in glioblastomas with oligodendroglioma component: a clinical study of 186 Chinese patients from a single institution

This study was designed to display the molecular genetic features of short-term survivors in glioblastomas with oligodendroglioma component (GBMO). A total of 186 patients with histological diagnosis of primary gliomas, including 11 GBMO-STS (short-term survivors, survival ≤12 months), 29 GBMO-LTS (relatively long-term survivors, survival >12 months), 36 anaplastic oligoastrocytoma (AOA) and 110 glioblastoma multiforme (GBM), enrolled in the study. An evaluation form was developed and used to document molecular pathological, clinical and treatment-associated parameters between subgroups. Kaplan–Meier plots for survival showed that the median progression-free survival (PFS) and overall survival (OS) of GBMO-STS were 5.0 and 10.0 months, respectively. Intergroup comparison revealed that the GBMO-STS harbored the most dismal prognosis than those with AOA, GBMO-LTS or GBM (P < 0.001 for PFS, P < 0.001 for OS, respectively). Cox regression analyses revealed that 1p/19q co-deletion and 19p polysomy were independent prognostic factors (P < 0.05). Pearson’s Chi square test demonstrated GBMO-STS exhibited lower 1p/19q co-deletion, IDH1 mutation rates than AOA or GBMO-LTS (P = 0.032, P = 0.045 for 1p/19q co-deletion; P = 0.034, P = 0.005 for IDH1 mutation, respectively) but higher chromosome 1q, 19p polysomy rates compared with AOA or GBM (P = 0.037, P = 0.030 for 1q polysomy; P = 0.017, P = 0.011 for 19p polysomy, respectively). Patients with glioblastomas with oligodendroglioma component concurrent with polysomy for chromosomes 1 and 19 always confers an unfavorable prognosis which needs our extra attention in clinic.