NCOG-16. VALIDATION OF EFFICACY OF CCRT FOLLOWED BY TEMOZOLOMIDE FOR NEWLY DIAGNOSED GBMS: 15-YEAR EXPERIENCE OF A SINGLE INSTITUTION

Abstract

Abstract PURPOSE The authors have analyzed the long-term follow-up results of chemotherapy with temozolomide (TMZ) during and after radiotherapy in patients with newly diagnosed glioblastoma (GBM). This study self-validates the effect of a treatment protocol that has been applied at a single institute for more than 18 years. MATERIALS AND METHODS Total 229 patients of newly diagnosed GBM patients who were treated with TMZ during and after radiotherapy from 2004 to 2018 in the authors’ institute were enrolled and analyzed in this retrospective study. Primary outcome was overall survival (OS), and progression-free survival (PFS) was the second outcomes. Long term survivors (LTS) were also reviewed retrospectively. 2021 World Health organization (WHO) classification has been used for this study. RESULTS The median follow-up period was 16.4 months (range, 1.3-171.1). Younger age (< 70 years old), higher KPS score (≥80 and ≥60), gross total resection (GTR), completion of the Stupp protocol, and salvage treatment in patients with the progressive disease showed significantly longer OS times than the other subgroups. Subgroup analysis has been gone through comparing LTS to non-LTS. non-GTR (42% vs. 67.6%, p < 0.001), preop KPS ( >60, 100% vs. 91.1%, p = 0.026) ( >80, 94% vs. 81%, p = 0.027), MGMT promoter methylation (42% vs. 26.3%, p = 0.034) were statistically significant factors that differentiate LTS from non-LTS. In our study, salvage treatment was significantly associated with increased survival in patients with PD. More specifically, if standard treatment was aborted, salvage treatment improved overall survival CONCLUSION Concurrent chemoradiotherapy using TMZ might be still effective for newly diagnosed GBM. Completing the Stupp protocol in patients with newly diagnosed GBM and salvage treatment in patients with the progressive disease might help achieve better survival.