Effect of Concomitant and Adjuvant Temozolomide on Prognosis and Survival in Glioblastoma Multiforme

Abstract

Objective: Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor in adults. The most common problem in the follow-up after GBM treatment is the lack of local control. This study aims to evaluate the efficacy and safety of Temozolomide (TMZ) in cases who received post-surgical radiotherapy and TMZ treatment in GBM compared to cases who received only radiotherapy treatment after surgery. Materials and Methods: The cases diagnosed with GBM were divided into two groups. The first group was divided into cases that received only radiotherapy after surgery, and the second group (combined treatment group) was divided into cases that received post-surgical radiotherapy and TMZ treatment. 28 cases who received radiotherapy and TMZ treatment after surgery and 26 cases who received only radiotherapy after surgery were included in the study. Local fractionated radiotherapy (60 Gy total dose: 2 Gyx5 days/week for 6 weeks) was applied to all cases. Only in the second group, 75 mg/m2/day 7 days/week orally, 200 mg/m2/day 5 days as monotherapy for 6 weeks, and six cycles of TMZ every 28 days were administered concomitantly. In addition to the effect of TMZ on prognosis and survival, the effects of age, gender, and resection size on progression-free survival (PSS) and overall survival (GSS) were evaluated in both groups. Results: There was no statistically significant benefit in terms of both PFS and OS in both groups for age and gender, a statistically significant benefit was found for resection size (total-subtotal). At the end of the study, PFS was 14 months in the combined treatment group and 6 months in the radiotherapy alone group (P<0.0001). OS was 16 months in the combined treatment group and 12.5 months in the radiotherapy alone group (P=0.0354). Conclusion: Combined (RT + TMZ) treatment after total surgical treatment was found to be more effective on prognosis and survival than radiotherapy alone.