Prospective study evaluating the radiosensitizing effect of reduced doses of temozolomide in the treatment of Egyptian patients with glioblastoma multiforme

PURPOSE In view of the documented toxicity of continuous daily radiosensitizer doses of temozolomide concomitant with radiation in the treatment of glioblastoma multiforme, we aimed to compare it with a different schedule of abbreviated radiosensitizer dosing. PATIENTS AND METHODS This was a randomized prospective study comparing toxicity and survival in 60 Egyptian patients with glioblastoma multiforme. Patients in arm I received temozolomide at a dose of 75 mg/m(2) daily with radiotherapy for 42 days, starting 4 weeks after surgery and reaching to a total radiation dose of 60 Gy/30 Fractions/6 weeks, while patients in arm II received temozolomide at a dose of 75 mg/m(2) concomitantly with the same radiotherapy schedule daily in the first and last weeks of the same radiotherapy program. RESULTS Common grade 1-2 adverse events were malaise in 28 patients (46.7%), followed by alopecia (40%) and nausea (26.7%). Grade 3-4 convulsion and decreased level of consciousness was seen in only four patients who were all from arm I. The median progression-free survival (PFS) for the entire study population was 10.6 months (95% confidence interval [CI] 7.3-14), and PFS at 12 months was 32%. The median PFS in arm I was 8.8 months (95% CI 5.9-11.7) and in arm II 11.5 months (95% CI 8.9-14.2), and PFS at 12 months for both arms was 32% and 30% respectively (P=0.571). The median overall survival (OS) of the whole group of patients was 14.2 months (95% CI 13-15.5), and OS was 70% at 12 months and 25% at 18 months. The median OS for patients in arm I was 12.3 months (95% CI 7.7-16.9), whereas in arm II it was 14.3 months (95% CI 14-14.7) (P=0.83). CONCLUSION Reduced radiosensitizer dosing of temozolomide concomitant with radiotherapy in glioblastoma multiforme exhibited comparable efficacy with a classic continuous daily schedule, though with better tolerability.