HG-27: ACUTE TOXICITY OF TEMOZOLOMIDE- VERSUS CISPLATIN-BASED RADIOCHEMOTHERAPY IN PEDIATRIC HIGH GRADE GLIOMA: COMPARATIVE ANALYSIS OF PROSPECTIVE, CONSECUTIVE, MULTICENTRIC AND MULTINATIONAL TRIALS OF THE GERMAN HIT-HGG STUDY GROUP

BACKGROUND: Due to lack of efficacy there is no standard treatment for pediatric high grade glioma (HGG) patients. Therefore, it appears to be essential to investigate acute toxicities of available treatments. We compared two large patient cohorts that have been treated in prospective phase II trials either with temozolomide- or cisplatin-based radiochemotherapy concerning acute toxicity during/after simultaneous radiochemotherapy. PATIENTS AND METHODS: Hematologic-, non-hematologic toxicity of children aged 3-18 years treated with radiochemotherapy according to HIT-GBM-C/GBM-D (cisplatinum/etoposide (PE) and PE plus ifosfamide (PEI) in combination with weekly vincristine injections during radiochemotherapy) or according to HIT-HGG-2007 (concomitant radiochemotherapy with temozolomide) were compared. Patients with histologically confirmed HGG (WHO grade III and IV) or unequivocal radiological diagnosis of diffuse intrinsic pontine glioma (DIPG) were included in these trials. For toxicity assessments, patients who were treated according to HIT-GBM-C/GBM-D/HIT-HGG-2007 in the interim phases (between two treatment protocols), were also included in the analysis. RESULTS: Hematotoxicity was available from 304 (leukocytes)/ 306 patients (thrombocytes), respectively. Grade 3-4 leukopenia was more frequent in the HIT-GBM-C/D (n = 88, 51.8 %) versus HIT-HGG-2007 cohort (n = 13, 9.7%); P < 0.001. Grade 3-4 thrombocytopenia was more likely in the HIT-GBM-C/D versus the HIT-HGG-2007 cohort (n = 21, 13.3% vs. 3 patients, 2.2%; P < .001). Grade 3-4 leukopenia appeared more often in children aged 3-7 years (45.2%) compared to older children: age 8-12, 32.5%; age 13-18, 24%; P = 0.034. Sickness/vomiting was more frequent in the platinum based radiochemotherapy; P < 0.001. CONCLUSION: Radiochemotherapy with temozolomide, in particular in children below 7 years of age, was less toxic than cisplatin-based treatment.