PRERADIATION CHEMOTHERAPY IN ADVANCED MEDULLOBLASTOMA - A PEDIATRIC-ONCOLOGY-GROUP PILOT-STUDY

Background. Children diagnosed with medulloblastoma whose tumor involv es the brain stem or has spread through the cerebrospinal fluid pathwa ys to other areas of the brain or spinal cord have a poor prognosis de spite therapy with surgery, craniospinal irradiation (CSI), and chemot herapy. Preradiation chemotherapy may improve the outlook for these pa tients. Methods. To further study the role and feasibility of preradia tion chemotherapy, children between the ages of 4 and 21 years diagnos ed with advanced medulloblastoma and measurable disease were enrolled in the Pediatric Oncology Group 8695 study. Patients were treated with a 9-week course of vincristine, cisplatin, and cyclophosphamide follo wed by CSI. Imaging films were reviewed centrally for eligibility and response to chemotherapy. Toxicity to chemotherapy and radiation as we ll as delays and modifications in subsequent CSI were recorded. Result s. Thirteen of 30 fully evaluable patients achieved complete or partia l response (43%) to chemotherapy. Toxicity was mostly fever and neutro penia after cyclophosphamide, which is predictable and tolerable. Radi ation therapy was delivered in full doses and volumes in most patients but was delayed in its start in most patients. Central review of film s revealed frequent use of different imaging modalities at baseline an d after therapy, making accurate assessment of tumor response difficul t. Conclusion. Preradiation chemotherapy with vincristine, cisplatin, and cyclophosphamide is active in patients with advanced medulloblasto ma but should be modified to minimize the risk of progressive disease while on therapy and to avoid delays in starting radiation therapy. Co nsistent use of the same neuroimaging modality is essential in documen ting response.