Should we continue temozolomide beyond six cycles in the adjuvant treatment of glioblastoma without an evidence of clinical benefit? A cost analysis based on prescribing patterns in Spain

Abstract
The standard adjuvant treatment for glioblastoma is temozolomide concomitant with radiotherapy, followed by a further six cycles of temozolomide. However, due to the lack of empirical evidence and international consensus regarding the optimal duration of temozolomide treatment, it is often extended to 12 or more cycles, even in the absence of residual disease. No clinical trial has shown clear evidence of clinical benefit of this extended treatment. We have explored the economic impact of this practice in Spain.