Stephanie E. Combs MD, Presenter: Research Grant, Schering-Plough Corporation Advisory Board, Schering-Plough Corporation Speaker, Schering-Plough Corporation

Johanna Wagner, Abstract Co-Author: Nothing to Disclose

Marc Bischof MD, Abstract Co-Author: Nothing to Disclose

Thomas Welzel, Abstract Co-Author: Nothing to Disclose

Jürgen Debus MD, PhD, Abstract Co-Author: Nothing to Disclose

Daniela Schulz-Ertner, Abstract Co-Author: Nothing to Disclose

Standard treatment for patients with glioblastoma multiforme (GBM) is currently considered to be postoperative radiochemotherapy (RCHT) with temozolomide (TMZ) with 75mg/m2. Previously, we had performed a phase I/II study with a dose of 50mg/m2 yielding comparable survival data in our instituton. In the present analysis, we evaluated toxicity and outcome in 160 patients with GBM treated with postoperative RCHT comparing these two dose regimens.

160 patients with histologically confirmed GBM were treated with postoperative RCHT with TMZ; 66 patients were female, 94 were male. Median age was 60 years (range 19-76 years). After primary diagnosis, a biopsy had been perfomed in 42 patients; a subtotal and total resection was conducted in 66 and 52 patients, respectively. Patient characteristics were equally distributed in both groups including age, extent of neuorosurgical resection as well as performance status.In all patients postoperative radiotherapy was performed with a median dose of 60 Gy in a median fractionation of 5 x 2Gy/week.Concomitant TMZ was applied at 50mg/m2 in 123 patients (group A), and 75mg/m2 in 37 patients (group B). Adjuvant cycles of TMZ were prescribed in 13 patients in group A and in 21 patients in group B.Patients were followed in 3-months intervals after RCHT, the median follow-up time was 13 months (range, 1-75 months).

Median overall survival (OS) in group A and in group B was 67% vs. 79% at 1 year and 43% and 49% at 2 years, respectively (p=0.65). Progression-free survival (PFS) was 49% vs. 54% at 1 year and 22% vs. 29% at 2 years (p=0.46).Patients receiving adjuvant cycles of TMZ showed OS of 93% vs. 65% at 1 year and 63% vs. 40% at 2 years (p=0.03); PFS in patients receiving adjuvant TMZ was 71% as compared to 45% in the RCTH-only group (p=0.008).Haematological toxicity was not statistically significant over the 6-week treatment course expect for significant decrease in platelets in week 6 (p=0.01) in group B.

Comparing these two dose regimens, outcome seems to be comparable in both groups. Lower dosing of temozolomide might be sufficient to treat patients with GBM during postoperative RCHT. However, longer follow-up and a larger group of patients are needed to corroborate these results

Combs, S, Wagner, J, Bischof, M, Welzel, T, Debus, J, Schulz-Ertner, D, Radiochemotherapy with Temozolomide for Primary Glioblastoma Multiforme Comparing Two Dose Regimens: 50 versus 75.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/6000913.html