Radiation Necrosis and White Matter Lesions in Pediatric Patients with Brain Tumors treated with Pencil Beam Scanning Proton Therapy
Menée à partir de données portant sur 171 patients pédiatriques atteints d'une tumeur cérébrale primitive traitée entre 1999 et 2015 (âge médian au diagnostic : 3,3 ans ; durée médiane de suivi : 49,8 mois), cette étude évalue la prévalence de nécroses symptomatiques et de lésions de la substance blanche après une protonthérapie par balayage à faisceau filiforme, en combinaison ou non avec une chimiothérapie concomitante
Purpose : To assess the rate of radiation necrosis (RN) and white matter lesions (WMLs) in pediatric patients with primary brain tumors treated with Pencil Beam Scanning (PBS) proton therapy (PT) with or without concomitant chemotherapy at the XXXX. Methods and Materials : Between 1999 and 2015, 171 pediatric patients (<18 years) were treated with PT. Median age at diagnosis was 3.3 years (range, 0.3-17.0) and the median delivered dose was 54 Gy (RBE) (range, 40.0–74.1). RN and WML were defined as a new area of abnormal signal intensity on T2-weighted images or increased signal intensity on T2-weighted images, and contrast enhancement on T1 occurring in the brain parenchyma included in the radiation treatment field, which did not demonstrate any abnormality before PT. Radiation necrosis and WML were graded according to the Common Terminology Criteria for Adverse Events v4.0. The median follow-up period for the surviving patients was 49.8 months (range, 5.9-194.7). Results : Twenty-nine (17%) patients developed RN at a median time of 5 months (range, 1-26), most of them (n=17; 59%) being asymptomatic (grade 1). Grade 2, 4 and 5 toxicities occurred in 8, 2 and 2 patients, respectively. Eighteen (11%) patients developed WML at a median time of 14.5 months (range, 2-62), most of them (n=13; 72%) being asymptomatic (grade 1). WML Grade 2 and 3 toxicities occurred in 4 and 1 patients, respectively. The 5-year RN-free and WML-free survival was 83% and 87%, respectively. In univariate analysis, neo-adjuvant (p=0.025) or any (p=0.03) chemotherapy, hydrocephalus before PT (p=0.035), and ependymoma (p=0.026) histology were significant predictors of RN. Conclusions : Children treated with PT demonstrated a low prevalence of symptomatic RN (7%) or WML (3%) compared to similar cohorts treated with either proton or photon radiotherapy. Chemotherapy, ependymomal tumors and hydrocephalus as an initial symptom were significant risk factors for RN.
http://www.redjournal.org/article/S0360-3016(17)34163-9/fulltext 2017