CTNI-73. OVERALL SURVIVAL OF NEWLY DIAGNOSED GLIOBLASTOMA PATIENTS TREATED BY STANDARD THERAPY IN COMPARISON TO STANDARD THERAPY PLUS TUMOR TREATING FIELDS

Abstract

Abstract BACKGROUND Tumor treating fields (TTFields; 200 kHz) have shown significant prolonged survival in newly diagnosed (ndGBM). TTFields are anti-mitotic, low intensity, intermediate frequency alternating electric fields. The applied fields disrupt the mitotic spindle, microtubule assembly and the segregation of intracellular organelles during cell division, leading to apoptosis or mitotic arrest. We compared overall survival (OS) between patients recently treated with standard therapy and standard therapy plus TTFields at our institution. METHODS Subjects (N=25) with ndGBM treated with standard therapy plus TTFields (STDTh-TTF) at our institution were included. Standard therapy (STDTh) consisted of surgical resection, followed by combined radiotherapy and chemotherapy (Temozolomide). In 3 cases, biopsies were performed instead of resection. The date of resection or biopsy was considered the entry date and was used in calculating survival. The study took place from July 2015 to April 2019. A matching control group of 25 subjects with ndGBM were treated with STDTh alone at our institution and were assembled from our database based primarily on date of resection or biopsy, and secondarily by age (2 subjects underwent biopsy in place of resection). When assembling the control group, the investigators were blinded to survival outcome. RESULTS Significantly greater overall survival was observed for the group treated by TTFields in addition to standard therapy (p < 0.001; Hazard ratio [HR] 0.21; 95% confidence interval [CI] 0.1–0.45; median survival time STDTh-TTF 31.7 months, STDTh 7.1 months). The groups were balanced with respect to sex, and no differences with respect to age (p = 0.13; STDTh-TTF mean 51.58 years, SD 8.8; STDTh mean 52.42 years, SD 8.7) or inclusion date (p = 0.22) by paired t-test were detected. CONCLUSIONS Our initial results appear promising with respect to overall survival benefit in patients undergoing TTFields treatment in addition to standard therapy.