ACTR-38. A SINGLE CENTER STUDY: LONG-TERM OUTCOMES OF COMBINED CHEMORADIATION THERAPY WITH TEMOZOLOMIDE FOR NEWLY DIAGNOSED GLIOBLASTOMA IN KOREAN PATIENT

In newly diagnosed glioblastoma (GBM), Temozolomide (TMZ) during and after radiation therapy has become standard treatment. This study describes the long-term use and follow-up results of this therapy for GBM. From 2004 to 2013 in a single institute, 112 Korean patients with newly diagnosed GBM were analyzed retrospectively. The Kaplan-Meier method, the two-sided log-rank test and Cox’s regression analysis was used to determine survival and its affecting factors. The toxicities of TMZ were evaluated using CTCAE v5.0. During the median follow-up period of 18.8 months, median PFS and OS were 9.2 and 20.3 months, respectively. This better survival outcome than the Stupp’s original study might be probably a large treatment effect of a single institution, ethnicity, and associated genetic factors. The TMZ during radiation therapy was completed in 108 patients (96.4%) and TMZ after radiation therapy in 59 patients (52.7%). Eight patients presented with grade 3 or 4 hematologic toxic effects during the protocol. Sixty-six patients (58.9%) received salvage treatment because of the poor response to adjuvant treatment or progression of the disease who achieved completion of adjuvant treatment was shown significantly longer median OS (p= 0.007) and PFS (p< 0.001). Age (< 60 years), preoperative KPS score (≥ 90), the extent of resection (≥ 78% by volumetric measurement, gross total resection), and completion of the Stupp’s protocol were significant factors affecting better survival. Between the sexes, and ages over 65 years did not show any significant difference among their groups. With marginal significances, the mutated IDH-1 and the methylated MGMT promoter showed longer median PFS(p= 0.075 and 0.777, respectively) and OS (p= 0.085 and 0.131, respectively). TMZ during and after radiation therapy might be effective and safe for newly diagnosed Korean patients with GBM. Further studies about various clinical and genetic factors affecting better survival are mandatory.