Radiochemotherapy in patients with primary glioblastoma comparing two temozolomide dose regimens

PURPOSE: To evaluate toxicity and outcomes in patients with primary glioblastoma (GB) treated with postoperative radiochemotherapy (RCHT) with temozolomide (TMZ) comparing two dose regimens. METHODS AND MATERIALS: A total of 160 patients with histologically confirmed GB were treated with postoperative RCHT with TMZ. Of the patients, 66 were female and 94 were male, with a median age of 60 years. After the primary diagnosis, a biopsy had been performed in 42 patients; a subtotal and total resection was conducted in 66 and 52 patients. Postoperative radiotherapy was applied with a median dose of 60 Gy with a median fractionation of 5 x 2Gy/week. Concomitant TMZ was prescribed at 50 mg/m(2) in 123 patients (Group A) and at 75 mg/m(2) in 37 patients (Group B). Patients were followed in 3-months intervals, with a median follow-up of 13 months. RESULTS: Overall survival (OS) rates in Group A vs. Group B were 67% and 79% at 1 year and 43% vs. 49% at 2 years, respectively (p = 0.69). Progression-free survival was 49% vs. 54% at 1 year and 22% vs. 29% at 2 years (p = 0.31). Hematologic toxicity was not statistically significant over the 6-week RCHT period except for a significant decrease in platelets during Week 6 (p = 0.01) in Group B. CONCLUSIONS: Overall survival seems to be comparable in both groups, although longer follow-up and a larger group of patients are needed to corroborate these results. Lower dosing of TMZ also is associated with a more beneficial toxicity profile.