Radiotherapy and sequential temozolomide compared with radiotherapy with concomitant and sequential temozolomide in the treatment of newly diagnosed glioblastoma multiforme

Our objective was to determine and compare effects of sequential temozolomide vs. concomitant plus sequential temozolomide with conventional radiotherapy, in patients with newly diagnosed glioblastoma multiforme, comparing two independent trials. Sixty-four patients were treated on two consecutive separate phase II studies that used identical eligibility criteria and the same radiotherapy (60 Gy, 2 Gy/day, after surgery) and adjuvant temozolomide (200 mg/m/day for 5 days/28 days until progression), but differed in the absence or presence of a concomitant treatment with temozolomide (75 mg/m/day) during radiotherapy. In the first protocol (1999-2002), 21 patients (median age of 64 years) received radiotherapy alone and sequential temozolomide; in the succeeding protocol (2002-2004), 43 patients (median age of 61 years) with similar characteristics received radiotherapy with concomitant and sequential temozolomide. Median number of adjuvant cycles was five in both trials. Median survival was similar in both studies (18 vs. 17.4 months); overall survival rates at 6, 12, 18 and 24 months of all the population were 89, 69, 45 and 24%. No statistically significant differences were found among prognostic factors considered. Hematologic toxicities were mild and similar, with grade 3-4 neutropenia in 5-7% and grade 3-4 thrombocytopenia in 7-10% of patients in the sequential phases, and grade 3-4 thrombocytopenia in 7% in the concomitant phase of temozolomide. We confirmed that temozolomide combined with radiotherapy is well tolerated and provides a survival advantage compared with historical data using radiotherapy alone. Nevertheless, a concomitant use of temozolomide during radiotherapy does not seem to improve survival, although it does not increase toxicity.