RADT-09. CHEMORADIOTHERAPY WITH TEMOZOLOMIDE VS. RADIOTHERAPY ALONE IN PATIENTS WITH IDH WILD-TYPE AND TERT PROMOTER MUTATION HISTOLOGICAL GRADE 2/3 GLIOMAS: A POSTHOC ANALYSIS OF A RANDOMIZED CONTROLLED TRIAL

Abstract PURPOSE In 2016, we initiated a signal center prospective randomized trial to compare chemoradiotherapy (CRT) with temozolomide (TMZ) to radiotherapy (RT) alone in patients with IDH wild-type and TERT promoter mutation histological grade 2/3 gliomas. This study demonstrated patients who received CRT had a longer median OS than those who received RT alone and found no statistical difference in PFS between the two groups. Now, we recruited more patients in the CRT group to further explore whether there were differences in PFS between patients treated with CRT and RT. Besides, we explored the effect of MGMT promoter (MGMTp) methylation status on OS and PFS in patients receiving CRT therapy in the STUPP schedule. METHODS We expanded the scope by enrolling 21 participants in the CRT group and extending the follow-up period. OS and PFS were analyzed using the log-rank test, and high-risk factors were explored through Cox regression analysis. RESULTS Patients’ median follow-up is 21.9 months. CRT group has a longer median OS (25.3 vs 17.2 months; P = 0.029, HR = 0.443) and PFS (14.6 vs 8.3 months; P = 0.0008, HR = 0.387) than the RT group. Multivariate analysis identified CRT as a favorable prognostic variable for both OS (P = 0.003) and PFS (P = 0.002). The status of MGMTp methylation did not affect OS (P = 0.560, HR = 1.30) and PFS (P = 0.75, HR = 0.88) in patients with IDH-wt/TERTp-mut receiving TMZ chemotherapy. CRT with TMZ did not significantly increase grade 3 or higher toxicities. CONCLUSIONS The long-term results confirmed that the OS and PFS benefits of the RT plus TMZ regimen exceeded those of the RT alone group in patients with IDH-wt/TERTp-mut gliomas.