P01.110 Elderly patients >65years of age with newly diagnosed Glioblastoma multiforme gain life time from treatment with Tumor Treating Fields and Temozolomide

Abstract Background Glioblastoma (GBM) is the most aggressive form of primary brain cancer in adults. The EF-14 trial was the first randomized controlled trial to report a survival benefit for newly diagnosed GBM patients in more than a decade with a survival rate greater than 10% at 5-years. A post hoc subgroup analysis of the elderly (>65 years) EF-14 populationshowed the greatest survival beneft from TTFields in this subgroup (HR = 0.51) and a survival at 5-years of 15% for patients treated with TTFields and maintenance TMZ compared to no survivors in the TMZ alone arm. Material and Methods An integrated survival model was calculated, incorporating Kaplan Meier Data of the subgroup over 65 years GBM patients from the EF-14 Trial with epidemiological data on long-term GBM survival. Future survival benefits were discounted at a rate of 3% (i.e., survival in future years was reduced by 3% per year). We also perfomed sensitivity analyses of the results and compared the results of our integrated survival model to regression based extrapolations of the trial data. Results Elderly patients treated with TTFields and TMZ achieved an undiscounted mean lifetime survival of 3.66 years compared to 1.32 years for patients treated with TMZ alone, resulting in a gain of 2.34 life years for TTFields plus TMZ. After application of the 3% discount rate for future survival benefits, the resulting life time survival is 3.04 vs. 1.29 life years respectively, resuling in 1.75 incremental life years gained. Conclusion In the subgroup of elderly patients of the EF-14 Trial treatment with TTFields plus TMZ resulted in a substantial increase of the mean lifetime survival of 1,75 life years compared to treatment with TMZ alone, despite the older age of the patients with a naturally lower potential for long-term survival. These results together with the low incidence of adverse events in the EF-14 trial indicate that it may be appropriate to opt for TTFields treatment in newly diagnosed GBM patients 65 years and older.