Clinical Outcomes among Children with Standard Risk Medulloblastoma Treated with Proton and Photon Radiotherapy: A Comparison of Disease Control and Overall Survival
Menée sur 88 patients pédiatriques atteints d'un médulloblastome à risque standard traité entre 2000 et 2009 par chimiothérapie en combinaison avec une radiothérapie (âge : 3 à 21 ans), cette étude multicentrique compare l'efficacité, du point de vue du contrôle de la maladie, de la survie sans récidive ou de la survie globale, d'une protonthérapie et d'une radiothérapie par faisceaux de photons
Purpose/Objective(s) : To compare long-term disease control and overall survival between children treated with proton and photon radiotherapy (RT) for standard risk medulloblastoma. Methods and Materials : This multi-institution cohort study includes 88 children treated with chemotherapy and proton (n=45) or photon (n=43) RT between 2000 and 2009. Overall survival (OS), recurrence-free survival (RFS) and patterns of failure were compared among the two cohorts. Results : Median (range) age at diagnosis was 6 yrs (3 - 21) for proton pts vs. 8 yrs (3 - 19) for photon pts (p=0.011). Cohorts were similar with respect to gender, histology, extent of surgical resection, craniospinal (CSI) RT dose, total RT dose, whether the RT boost was delivered to the posterior fossa (PF) or tumor bed (TB), time from surgery to RT start, or total duration of RT. RT consisted of a median (range) CSI dose of 23.4 Gy (18 - 27) and a boost of 30.6 Gy (27 - 37.8). Median (95% CI) f/up time is 6.2 yrs (5.1 – 6.6) for proton pts vs. 7.0 yrs (5.8 – 8.9) for photon pts. There was no significant difference in RFS or OS between pts treated with proton vs. photon RT: 6 yr RFS 78.8% vs. 76.5% (p=0.948) and 6 yr OS 82.0 vs. 87.6% (p=0.285). On multivariable analysis, there was a trend for longer RFS with female gender (p=0.058) and higher CSI dose (p=0.096), and for longer OS with female gender (p=0.093). Patterns of failure were similar among the two cohorts (p=0.908). Conclusions : Disease control with proton and photon radiotherapy appears equivalent for standard risk medulloblastoma.