Artikel
Prolonged temozolomide maintenance cycles after concomitant radiotherapy and temozolomide in glioblastoma
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Veröffentlicht: | 8. Juni 2016 |
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Gliederung
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Objective: Dose-intensified temozolomide (TMZ) regimens have not led to extended overall survival (OS) in newly diagnosed glioblastoma. We investigated the effect of prolonged TMZ maintenance therapy on progression free survival (PFS) and OS.
Method: We included 140 patients > 18 years of age who received surgery and concomitant radio-chemotherapy with TMZ and TMZ maintenance therapy in a retrospective single center cohort study. Clinical key parameters included age, O6-methylguanine-DANN methyltransferase (MGMT), extent of resection (EOR), Karnofsky performance status and the number of TMZ cycles and adverse events. For statistical analysis patients were considered who stopped TMZ within the regular 6 cycles because of side effects (group A, n=30), who completed 6 cycles of TMZ without progression (group B, n=20), and who continued TMZ beyond 6 cycles (group C, n=36).
Results: A total of 86/140 patients were eligible for Kaplan-Meier analyses and Cox regression, 54 patients were excluded because of progression during regular TMZ maintenance cycles. In group A, median PFS time was 7.7 months (95% CI 5.8-12.0) and OS time was 12.5 months (95% CI 10.3-19.1). In group B, median PFS time was 11.8 months (95% CI 9.5-17.9) and OS time was 19.1 months (95% CI 13.7-55.5). In group C, median PFS time was 19.1 months (95% CI 13.7-38.3) and OS time 28.6 months (95% CI 22.9-open). Adjusted Cox regression did not show a significant difference for patients in groups B compared to C for progression (p=0.11) or death (p=0.62). EOR (RR 0.41, p=0.005), Age (RR 0.37, p=0.008) and MGMT gene promoter methylation (RR 0.36, p=0.0009) were confirmed as significant prognostic factors for OS.
Conclusions: Our data suggest 1. no improvement of PFS and OS by a prolongation of TMZ maintenance therapy, and 2. the mandatory need of multivariate Cox regression to validate the treatment efficacy in any retrospective study.