Clinical outcome of concomitant chemoradiotherapy followed by adjuvant temozolomide therapy for glioblastaomas: single-center experience

Abstract

Introduction: The use of radiotherapy plus temozolomide administered concomitantly with and after radiotherapy for glioblastoma was recently shown to improve median and 2-year survival in a large international multicenter study. To compare this result in routine clinical practice, an audit of the management and outcome of patients with glioblastoma at our institute was performed.

Methods: A total of 79 patients with pathologically confirmed glioblastoma were treated with radiotherapy (daily fractions of 2 Gy for a total of 60 Gy) combined with temozolomide at a dose of 75 mg/m(2) per day, followed by 6 cycles of adjuvant temozolomide (150-200 mg/m(2), 5 consecutive days per month). The primary end point was overall survival (OS). Secondary endpoints included progression-free survival (PFS) and toxicity. We evaluated the clinical outcome of concomitant chemoradiotherapy for newly diagnosed glioblastomas at a single institute in Korea.

Results: The median age was 52 years (15-76 years), 47 patients were male and 32 patients were female. 92.4% of the patients had undergone debulking surgery. The median overall survival (OS) was 18.3 months (95% CI, 16.3-20.1 months), and the time to progression was 6.7 months (95% CI, 5.2-8.3 months). The 1-year and 2-year survival rates were 70.1% and 37.1%, respectively. In the retrospective analysis, the patients with a post-operative KPS over 80 showed more prolonged survival than those who had a KPS less 80 (23.1 months vs. 13.4 months; p<0.001). Age and extent of surgery did not emerge as significant factors. Twenty-four patients (30%) were treated with low-dose continuous temozolomide therapy after the tumor had recurred. Hematologic toxicity was the main adverse effect, occurring in seven patients (8.8%). Patients with lymphopenia were not reported.

Conclusions: This study is the largest study of radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma in Korean patients, who share a common genetic feature. The median and 2-year survival outcomes in this study are comparable to the previous reports. However, for the recurrent glioblastomas refractory to temozolomide, further clinical trials using other agents should be studied continuously in the future.