TREATMENT OUTCOMES OF CHILDREN AND ADOLESCENTS WITH AVERAGE-RISK MEDULLOBLASTOMA: MULTICENTER STUDY IN KOREA

Abstract

Medulloblastoma (MBL) is the most common primary malignant brain tumor of childhood. Because there are no definite estimates and analyses for clinical outcomes in average-risk MBL in Korea, we investigated the clinical characteristics and treatment outcomes of children and adolescents with average-risk MBL. Questionnaires about the demographics, clinical characteristics, treatments, and outcomes of children and adolescents diagnosed with average-risk MBL between 2000 and 2010 were sent to the member hospitals of the Korean Society of Pediatric Neuro-Oncology (KSPNO). From 16 hospitals, 159 patient records were collected, and retrospective review and analysis of them were performed. The median age at diagnosis was 8.5 years, and the male:female ratio was 102:57. Their histological subtypes were as follows: 107 classic, 14 large cell/anaplastic, 10 desmoplastic, and 28 unknown or other types. All patients had undergone surgery, and radiation therapy (RT) was performed in 153 patients. Fifty-three patients were initially treated with the KSPNO-M051 treatment protocol, and 106 patients were treated with other protocols. Median follow-up was 40 months, and 5-year event-free survival (EFS) and overall survival (OS) were 66.2 ± 4.3% and 80.0 ± 3.9%, respectively. Forty-eight patients showed events, with the majority being relapse or progression of disease. Compared with the patients without the large cell/anaplastic subtype (5-year EFS and OS of 68.4 ± 4.4% and 81.3 ± 4.0%, respectively), patients with the large cell/anaplastic subtype showed a tendency toward poor outcomes (EFS 49.0 ± 13.6%, OS 68.8 ± 13.1%) without reaching statistical significance. Comparison of outcomes between groups treated with craniospinal RT >3000 cGy (36 patients) and <3000 cGy (98 patients), with EFS of 73.8 ± 7.5% and 63.5 ± 6.2% and OS of 90.7 ± 5.1% and 81.3 ± 5.0%, showed no significant differences. The clinical outcomes of childhood average-risk MBL in Korea were acceptable but slightly lower than those of patients in Western countries. These results demonstrate the need for prospective multicenter studies and further biologic investigations of average-risk MBL in Korea.