136 Complete Resection of Contrast-Enhancing Tumor Volume is Associated With Improved Survival in Recurrent Glioblastoma Results From the DIRECTOR Trial

Abstract INTRODUCTION: The role of reoperation for recurrent glioblastoma is still unclear because of the lack of prospective studies. Here, we report on the association of clinical outcome with surgery for recurrent glioblastoma including the volumetric extent of resection in the well-characterized patient cohort of the DIRECTOR trial. This prospective randomized multicenter study evaluated the effect of 2 different dose-intensified temozolomide regimens at first recurrence of glioblastoma. METHODS: We analyzed prospectively collected clinical, molecular, and imaging data from the DIRECTOR cohort (n = 105). Imaging data were available from 87 patients. Volumetric analysis was performed based on gadolinium (Gd) enhancement on magnetic resonance imaging and correlated with progression-free survival (PFS) and overall survival (OS). Proportional hazards models were applied to obtain prognostic factors. RESULTS: Seventy-one of 105 patients received surgery at recurrence. Prognostic factors such as age (P = .358), O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation (P = .965), IDH-1 mutation (P = .724), Karnofsky performance score (P = .880), or steroid intake before randomization (P = .950 were balanced between patients with and without reoperation. Mean tumor volumes at study entry were smaller in patients who had received surgery than in patients without (3.0 cm3 [range 0-37] vs 6.8 cm3 [range 1-23], P < .001). The outcomes in patients with/without surgery at recurrence were similar for PFS (2.0 months vs 1.9 months, P = .1974) and OS (9.2 months vs 9.4 months, P = .9538). Among patients who underwent reoperation, postsurgery imaging was available in 59 cases. In these patients, complete resection of Gd-enhancing tumor (n = 39) vs residual detection of Gd enhancement (n = 20) was associated with significantly improved OS (11.5 months [95% CI 9.3-15.1] vs 6.7 months [95% CI 5.2-9.5], P = .006). CONCLUSION: Surgery at first recurrence of glioblastoma seems to improve outcome if complete resection of Gd-enhancing tumor volume is feasible.