Temozolomide rechallenge in recurrent glioblastoma: When is it useful?

Aim: To identify patients with recurrent glioblastoma after temozolomide (TMZ) concurrent with and adjuvant to radiotherapy who could benefit from TMZ rechallenge at the time of disease progression. Methods: We retrospectively evaluated 106 glioblastoma patients who had nonprogressive disease at first magnetic resonance imaging after completion of TMZ concurrent with and adjuvant to radiotherapy, a treatment-free interval (TFI) of at least 8 weeks and received TMZ rechallenge or a nitrosourea at the time of progression. Results: In patients with TFI ≥5 months, median survival was 17.7 and 11.6 months and median progression-free survival was 8.1 and 5.8 months in the TMZ and nitrosourea group, respectively. Longer TFI was associated with reduced risk for death (p = 0.002) and for disease progression (p = 0.005). Conclusion: TFI ≥5 months represents a predictor of retained TMZ sensitivity.