MEDB-26. Outcomes of children with standard-risk and high-risk medulloblastoma treated with pre-irradiation chemotherapy and risk-adapted craniospinal irradiation: a report on patients from the Polish Pediatric Neuro-oncology Group

BACKGROUND: The last two decades have witnessed several efforts to minimize the adverse sequelae of craniospinal irradiation (CSI), a standard of care treatment modality in medulloblastoma. This has been accomplished by adding chemotherapy to the treatment backbone. The use of pre-irradiation chemotherapy has also been previously reported. In one of the largest studies to date, we analyze treatment outcomes in children with standard and high-risk medulloblastoma treated with pre-irradiation chemotherapy followed by reduced-dose radiotherapy in SR and maintenance chemotherapy. METHODS: Data from the Polish Pediatric Neuro-oncology Group (PPNG) was analyzed in patients greater than 3 years of age with newly-diagnosed medulloblastoma. RESULTS : Among 138 patients, median age at diagnosis was 7.9 years and median follow-up was 5.5 years. Comprehensive molecular subgrouping was not available for all patients at the time of data collection. Of 60 standard-risk patients, there was pre-irradiation disease recurrence in one patient. One patient expired prior to radiation due to metastatic disease. Of 78 high-risk patients, one had pre-irradiation recurrence. Overall survival (OS) for high-risk patients at 3 and 5 years (± standard error) was 89.2 ± 4.0% and 81.3 ± 5.8%, respectively. OS for standard-risk patients at 3 and 5 years was 92.5 ± 3.8% and 88.2 ± 5.1%, respectively. Among high-risk patients, event-free survival (EFS) at 3 and 5 years was 82.5 ± 5.3% and 81.0 ± 5.6%. Among standard-risk patients, 3-year EFS was 89.2 ± 4.6% and 5-year EFS was 86.8 ± 5.3%. CONCLUSION : This study demonstrates promising survival outcomes in pediatric medulloblastoma patients treated with pre-irradiation chemotherapy followed by reduced-dose CSI and adjuvant chemotherapy. Such an approach may be helpful if delays in starting radiotherapy are expected, which is usually the case in many institutions around the globe.