gms | German Medical Science

Objective: Optune is a novel treatment that is approved for the treatment of patients with newly diagnosed glioblastoma (GBM) and also for patients with recurrent high grade glioma (HGG). Alternating electric fields of low intensity (1-3 V / cm) and intermediate frequency (200 kHz) are delivered to the tumor in the brain. Here we report our experience with TTFields in 26 patients at Charité over the last year and the factors that could affect therapy compliance.

Methods: Since June 2015 twenty-six patients with a diagnosed HGG have been treated with Optune in our hospital. Patients were carefully introduced to the therapy. Compliance is a crucial indicator for the acceptance but also for the efficacy of the therapy. According to the EF-11 trial and PRiDe registry optune therapy should be applied at least 18 h per day (Compliance >75 %) to be efficient. Compliance reports were generated at the monthly routine check of the device.

Results: Patients had newly diagnosed GBM (n=17) or first recurrence of HGG (n=9). Mean age at therapy start was 47.9 years (range 25-70). Gender distribution female to male was 1:1.7. Mean treatment compliance was 87% in the total population (range 67-96%) independent of age, sex (female 85.3±5.8 % vs. male 87.6±7.3 % [Mean±SD], p=0.41) and stage of disease (newly diagnosed 88.5±5.4 % vs. recurrent 84.2±8.0 % [Mean±SD], p=0.12). Regression analysis reveals no negative correlation between age and compliance or inter-sex differences. Our data showed that the compliance is not negatively correlated with time on treatment and compliance in time course was stable once therapy was established..

Conclusion: Therapy compliance is not negatively influenced by age. In contrast, older patients even at the age of around 70 years showed a remarkable average compliance far above 80%. Furthermore, compliance was equal in female and male population. In the light of a female to male ratio of 1:1.7 reflecting a typical GBM patient population (1:1.64), we assume that Optune is accepted by both male and female patients without difference. In addition, there was no significant difference of compliance between patients with newly diagnosed and recurrent GBM suggesting that the stage of the disease does not play a big role in the acceptance and feasibility of the treatment. Since the therapy takes time to be fully effective, compliance should be maintained on a high level. Compliance did not correlate negatively with time on treatment nor drop substantially below 75% in time course. Once patients are on therapy they are compliant over the course of treatment, making Optune suitable for long-term therapy.