Abstract

INTRODUCTION

Glioblastoma multiforme (GBM), a grade IV malignant glioma, is the most common primary brain tumor in adults. Following biopsy or resection, radiotherapy (RT) and concomitant and adjuvant temozolomide (TMZ) use (6 cycles) have become the standard of treatment for newly diagnosed GBM cases. Although the original treatment regimen involves the use of 6 cycles of TMZ, some centers administer prolonged treatment up to 12 or more cycles in non-progressive patients in the hope of achieving better outcome. This form of administration is controversial. The main purpose of our study is to determine whether prolonging TMZ treatment (from 6 months to 12 months) is beneficial in patients treated with a standard combined treatment approach in terms of disease-free survival (DFS) and OS.

METHODS

Between 2012-2019 years we analyzed 180 GBM patients retrospectively and included 100 patients who met the criteria for inclusion in the study.

RESULTS

100 GBM patients were retrospectively examined. Median OS was 21 (18.47-23.52) months overall, while it was 24 (18.21-29.78) months in recipients of 6 cycles of TMZ, it was 22 (18.50-25.49) months in the group receiving 12 cycles of TMZ, and 10 months in those who could not complete adjuvant therapy. There was no statistically significant difference between 6 cycles and 12 cycles of TMZ treatment (p = 0.55). Patients who could not complete the adjuvant therapy had lower survival and this group had a statistically significant OS difference compared to patients receiving 6 and 12 cycles of TMZ (p = 0.04 and p = 0.024, respectively).

DISCUSSION AND CONCLUSION

Our study indicate that prolongation of adjuvant TMZ treatment in GBM patients do not provide an additional survival advantage regardless of age, performance status and tumor characteristics. Additionally, GBM patients who could not complete standard 6-cycle adjuvant treatment have lower survival rates.