QOL-22. USE OF TUMOR TREATING FIELDS THERAPY WITH ADJUVANT TEMOZOLOMIDE AND IMMUNOTHERAPY FOR NEW DIAGNOSED GLIOBLASTOMA (NDGBM)

Abstract

Abstract BACKGROUND Treatment options for GBM remain limited, and novel approaches are required. One of them, Tumor Treating Fields (TTFields) therapy, is a non-invasive treatment modality that delivers low intensity, intermediate frequency, alternating electrical fields and increases survival through multiple mechanisms, including disrupting cell mitosis, triggering tumor cell death, and expanding CD8+ cytotoxic lymphocytes. METHODS In this prospective study, adult patients with ndGBM underwent standard-of-care treatment with maximal resection, followed by radiotherapy and temozolomide. Use of TTFields therapy, with a recommended daily use of ≥ 18 hours/day, throughout adjuvant temozolomide treatment and with immunotherapy, was investigated. RESULTS Eight patients received TTFields therapy. Use of TTFields was 2, 5, 6, 6, 8, 8, 10, and 16 months with an average of 10.2 months. The patient with the lowest use developed a grade 1 papulopustular scalp rash and discontinued use. Monthly average daily use ranged from 0% to 87%. Average daily use over treatment was 39%, 47%, 48%, 53%, 67%, 69%, 78%, and 83%. None of the patients achieved the goal for daily use every month. Four patients had a daily use ≥ 80% for at least one month of treatment. Except for one patient, whose daily use increased from 72% in the first month to 79% in the last month, all other patients down-trended in TTFields use. Six patients completed EORTC-QLQ-C30 surveys throughout the study. 3/8 had an overall increase in their global quality of life scale, 3 patients had a decrease, and 2 patients did not complete the survey. DISCUSSION In this study, the use of TTFields was suboptimal. We presume that with multiple treatments in the adjuvant phase including 6 cycles of temozolomide and optional TTFields use, patients did not recognize the potential therapeutic benefit of continued TTField therapy use and opted to remain only in the immunotherapy treatment.