Concurrent and adjuvant temozolomide-based chemoradiotherapy schedules for glioblastoma. Hypotheses based on two prospective phase II trials

AIM: To investigate the impact of nonstandard concomitant temozolomide (TMZ) administration in two prospective phase II studies for glioblastoma (GBM). PATIENTS AND METHODS: From October 2000 to June 2008, 104 patients were enrolled in two studies: 25 in RT-TMZ-10.00 and 79 in RT-TMZ-01.04. Adjuvant radiotherapy (RT) was used with a total dose of 59.4 Gy (1.8 Gy/day). Patients received concomitant TMZ (75 mg/m(2)/day) from Monday to Friday during the first and last weeks of RT in the RT-TMZ-10.00 study and from Monday to Friday during all weeks of RT in the RT-TMZ-01.04 trial. Adjuvant TMZ (200 mg/m(2)) was administered for 5 days every 28 days. RESULTS: Median progression-free (PFS) and overall survival (OS) were 9 and 16 months, respectively, with no significant difference between the two groups (p = 0.5 and 0.14, respectively). The 2- and 5-year OS rates were 32 and 3 %, respectively, and similar to those observed with standard treatment regimens. CONCLUSION: Our data support the hypothesis that adjuvant TMZ is more important than concomitant chemotherapy (CH) and that RT is the more important element of the concomitant treatment schedule.