PREIRRADATION CHEMOTHERAPY IN CHILDREN WITH HIGH-GRADE ASTROCYTOMA - TUMOR RESPONSE TO 2 CYCLES OF THE 8-DRUGS-IN-1-DAY REGIMEN - A CHILDRENS-CANCER-GROUP STUDY, CCG-945

Purpose. This study was undertaken to evaluate the radiographic respon se to two cycles of chemotherapy prior to irradiation in newly diagnos ed children with high-grade astrocytomas. Patients and methods. One hu ndred and thirty children less than 21 years of age with newly-diagnos ed highgrade astrocytoma were treated with the 'eight-drugs-in-one-day ' chemotherapy regimen as part of a phase III multi-institutional Chil drens Cancer Group (CCG) trial. Computerized Tomographic (CT) or Magne tic Resonance Image (MRI) scans, obtained after two cycles of chemothe rapy had been administered, were compared with post-operative scans to determine treatment response. Scans were evaluated by institutional r adiologists, and were reviewed centrally by a single neuroradiologist. Results. Of 79 patients with evaluable post-operative residual tumor on CT or MRI scans, 26 (33%) were determined on institutional evaluati on to have had an objective response. However, central review of scans documented responses on only 14/79 (18%). A significantly higher resp onse rate on central review was observed for those children 36 months of age or less at study entry than for older children (33% v 11%; p < 0.001). However, a higher disease progression rate was also observed f or those children 36 months of age or less than for older children (21 % v 2.6%; p < 0.001). Conclusion. In this study, the largest yet repor ted in newly-diagnosed children with high-grade astrocytomas, the chem otherapy regimen has activity in younger children. The differences in response rates reported by institutional and central review highlight the difficulties inherent in assessing response to brain tumor therapy . However, the study does demonstrate the consistent ability of radiol ogists to identify disease progression within the institutional and ce ntral reviews.