QOL-02. FACTORS INFLUENCING COMPLIANCE IN TTF TREATMENT – THE COMPTUNE STUDY

INTRODUCTION Recently, tumor treating fields (TTFields) were established for the treatment of newly diagnosed glioblastoma (nGBM). A crucial parameter for TTFields efficacy is compliance to treatment. In this prospective study, we assessed 5 psychological domains known to influence treatment compliance using a standardized interview in nGBM patients. The results of this psychological assessment were correlated to TTF compliance. METHODS A cohort of 49 nGBM patients (female 22; male 27, median age 62 years) were recruited. Most patients received a gross total resection (51%), the postsurgical treatment consisted of concomitant radiochemotherapy plus TTF in most cases (81%), only 2 patients received chemotherapy only, and 7 patients were additionally enrolled in clinical drug trials. The psychological assessment system consisted of 5 domains: Social support, confidence in treatment efficacy, communication status about treatment, anxiety, and depression. The interview was repeated every 8 weeks over a period of 8 months or if patients stopped treatment or developed second tumor progression. Additional phone interviews were conducted every 4 weeks. RESULTS Median and mean compliance was 98% and 81.6%, respectively (range 5%-100%), drops of compliance below 75%, which were classified as a threshold value, occurred 2259 times. Over-dispersed Poisson and multivariate negative binomial regression analysis revealed depression to be significantly correlated with the number of drops below 75% and with the mean compliance in the first 4 months of treatment. In addition, at later time points, confidence in treatment efficacy significantly correlated with the number of drops below 75%. All other domains did not appear to be associated with TTF treatment compliance. CONCLUSION Overall, compliance to TTF was high, however, drops below 75% of compliance occurred frequently during the measurement periods. In the initial treatment phase, depression was associated with these events, whereas confidence in treatment efficacy was correlated at later time points.