Abstract
OBJECTIVES: The advent of integrated genomics has fundamentally changed our understanding of medulloblastoma. Although survival differences have been shown to exist between the four principle subgroups, treatment related differences have yet to be elucidated. We sought to delineate these differences at a large referral centre. METHODS: All patients over age 3 treated with surgery, craniospinal irradiation and adjuvant chemotherapy were identified at the Hospital for Sick Children in Toronto from 1998-2012. RESULTS: Ninety-four patients were identified who met our inclusion criteria. Two periods were identified, those patients treated prior to 2006 as per the open protocols of the Children's Oncology Group (CCG9961, POG9631), and patients treated after 2006 treated as per the SJMB03 protocol. Five-year progression free survival over the entire cohort was 78%. When stratified by treatment, 5 year survival pre and post 2006 were identical (76.8% pre-2006 and 79.3% post-2006). When re-analysed in a subgroup specific manner, we find no significant differences in progression-free survival pre and post 2006. Strikingly, we found that Group 3 and 4 patients have excellent survivals compared to those previously reported, with 5 year progression-free survival in average risk Group 4 patients of over 90% and over 75% in average risk Group 3 patients regardless of treatment protocol. SHH patients did relatively poorly across both treatment protocols with 5 year progression free survival of 60% likely owing to a high proportion of TP53 mutated patients. CONCLUSIONS: In a cohort of homogenously treated patients over age 3, progression free survival appears to be improved compared to initial reports based on retrospective cohorts. The impact of subgroup affiliation in children over age 3 needs to assessed in large prospectively treated cooperative protocols to determine the subgroup specificity of treatment regiments.