Long-term follow up of patients with WHO grade 2 oligodendroglioma

Abstract

Purpose Since the introduction of the molecular definition of oligodendrogliomas based on isocitrate dehydrogenase (IDH)-status and the 1p19q-codeletion, it has become increasingly evident how this glioma entity differs much from other diffuse lower grade gliomas and stands out with longer survival and often better responsiveness to adjuvant therapy. Therefore, apart from using a molecular oligodendroglioma definition, an extended follow-up time is necessary to understand the nature of this slow growing, yet malignant condition. The aim of this study was to describe the long-term course of the oligodendroglioma disease in a population-based setting and to determine which factors affect outcome in terms of survival. Methods All adults with WHO-grade 2 oligodendrogliomas with known 1p19q-codeletion from five Scandinavian neurosurgical centers and with a follow-up time exceeding 5 years, were analyzed regarding survival and factors potentially affecting survival. Results 126 patients diagnosed between 1998 and 2016 were identified. The median follow-up was 12.0 years, and the median survival was 17.8 years (95% CI 16.0–19.6). Factors associated with shorter survival in multivariable analysis were age (HR 1.05 per year; CI 1.02–1.08, p < 0.001), tumor diameter (HR 1.05 per millimeter; CI 1.02–1.08, p < 0.001) and poor preoperative functional status (KPS < 80) (HR 4.47; CI 1.70–11.78, p = 0.002). In our material, surgical strategy was not associated with survival. Conclusion Individuals with molecularly defined oligodendrogliomas demonstrate long survival, also in a population-based setting. This is important to consider for optimal timing of therapies that may cause long-term side effects. Advanced age, large tumors and poor function before surgery are predictors of shorter survival. Graphical Abstract

Long-term outcomes of CNS WHO grade 2 oligodendroglioma in adult patients: a single-institution experience

“…This study presents the largest patient cohort analysis on 1p19q-codeleted ODG WHO grade 2 conducted by a single institution to date, providing a comprehensive analysis of long-term outcomes and prognostic factors for survival. As detailed in Table 3 , the observed median PFS of 6.8 years and median OS of 18.4 years in our cohort are consistent with the favorable prognosis associated with this molecular subtype, consistent with previous studies [ 6 , 14 – 17 ]. Notably, these results are better compared to the 24.7 months of median PFS, and 50.8 months of median OS reported in our recent study involving 95 patients with anaplastic ODG at our institution [ 18 ].…”

Long-term Outcomes of CNS WHO grade 2 Oligodendroglioma in Adult Patients: A single- institution experience

“…This study presents the largest patient cohort analysis on IDH-mutant, 1p19q-codeleted ODG WHO grade 2 conducted by a single institution to date, providing a comprehensive analysis of long-term outcomes and prognostic factors for survival. As detailed in Table 3, the observed median PFS of 6.8 years and median OS of 18.4 years in our cohort are consistent with the favorable prognosis associated with this molecular subtype, consistent with previous studies [6, [14][15][16][17]. Notably, these results are better compared to the 24.7 months of median PFS, and 50.8 months of median OS reported in our recent study involving 95 patients with anaplastic ODG at our institution [18].…”

“…Previous studies have reported contrast enhancement in 25 to 56% of patients with lower grade ODG [14,17,[26][27][28], a range comparable to the 31.2% observed in our study. Several studies have also identi ed contrast enhancement on MRI scans as a potential prognostic factor in IDH-mutant gliomas [14,26,29].…”

“…In contrast to studies indicating that the EOR in uences survival outcomes, according to the ndings studied by Carstam et al, it was reported that initial surgical strategies do not affect survival outcomes. However, this study identi es limitations in accurately evaluating the EOR due to the characteristics of a multicenter study, as well as the absence of postoperative MRIs in the initial study participants [17]. Additionally, a recent study reported that while the EOR impacts PFS, it does not affect OS [16].…”

“…Several studies have also identi ed contrast enhancement on MRI scans as a potential prognostic factor in IDH-mutant gliomas [14,26,29]. In contrast, some studies have reported no correlation between contrast enhancement and PFS or OS [16,17]. A comparative study on IDH mutation status reveals that the presence of contrast enhancement in diffuse IDH wild-type gliomas had no signi cant impact on survival, whereas its presence is associated with a poorer prognosis in IDH-mutant gliomas [26].…”