10154- ACT-8 CURRENT STATUS AND PROBLEMS OF GLIOBLASTOMA TREATMENT USING THE NOVOTTF-100A SYSTEM

Abstract PURPOSE The AC electric field tumor therapy system (NovoTTF-100A system: NovoTTF) in combination with temozolomide chemotherapy is now covered by insurance as maintenance therapy for glioblastoma. While the system is expected to prolong survival, it is recommended to be used for at least 18 hours per day (75% of the time), making it difficult for some patients to continue using the system. We investigated the effect of NovoTTF usage rate on the efficacy of treatment based on our own experience. METHOD Thirteen patients with first-episode glioblastoma treated with NovoTTF between January 1, 2020 and June 30, 2024 were included in this study. 6 patients in the high daily use rate group (>75%) and 7 patients in the low daily use rate group (<75%) were compared. RESULTS The median age of patients in the high-use group was 63 (50-78) years, and 74 (50-79) years in the low-use group. 2-year survival rates were 33.3% and 0%, respectively, with some patients in the high-use group surviving longer than 2 years. Skin lesions occurred in 33.3% of the high-use group and 71.4% of the low-use group, with a higher incidence of skin lesions in the low-use group. The mean daily use rate was 86.0% (78.8-97.0) in the high use group and 38.3% (26.0-69.0) in the low use group, and the mean days of use were 342.5 (5-1086) and 88.7 (20-240), respectively. The median KPS was 90 (50-100) in the high use group and 90 (60-100) in the low use group. CONCLUSION The high NovoTTF use rate group tended to be younger and had a lower frequency of skin lesions, and there were cases of long-term survival. It is important to increase the use of NovoTTF for elderly patients and skin disorders.