Background: Although craniospinal irradiation (CSI) of 2340 cGy plus tumor booster with chemotherapy have been established as a standard treatment of childhood average-risk (AvR) medulloblastoma (MBL) in Western counties, there are a few recent reports in outcomes of AvR MBL using this strategy in Korean and other Asian children. We investigated the outcome of the Korean children with AvR MBL who were treated with CSI <2500 cGy and chemotherapy.

Methods: Between January 2001 and December 2010, clinical characteristics and outcomes of 42 patients who were diagnosed with AvR MBL postoperatively and treated with radiation including CSI <2500 cGy and chemotherapy in Seoul National University Children's Hospital were analyzed.

Results: Their median age was 9 years (range: 3-18.8), and 29 were male. Histological subtypes were classic type in 28 patients, nodular/desmoplastic in 7, and large cell/ anaplastic (LCA) in 7. All the patients received adjuvant radiotherapy (CSI with median 2340 cGy and booster) and multiagent chemotherapy as the first-line treatment. With a median follow-up of 54 months, 12 patients experienced relapse or progression of the tumor. The 3- and 5-year disease-free survival (DFS) rates were 78.0%±6.5% and 75.0%±6.9%, respectively, and overall survival (OS) rates were 85.3%±5.6% and 76.8%±6.9%, respectively. The LCA subtype was associated with poorer DFS (P=0.023) and OS (P=0.008), compared with non-LCA subtypes.