Radiation Necrosis and White Matter Lesions in Pediatric Patients With Brain Tumors Treated With Pencil Beam Scanning Proton Therapy.

Abstract

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 PSI.

METHODS AND MATERIALS:

Between 1999 and 2015, 171 pediatric patients (age <18 years) were treated with PT. Median age at diagnosis was 3.3 years (range, 0.3-17.0 years), and the median delivered dose was 54 Gy (relative biological effectiveness) (range, 40.0-74.1 Gy). Radiation necrosis and WMLs 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 WMLs were graded according to the Common Terminology Criteria for Adverse Events, version 4.0. The median follow-up period for the surviving patients was 49.8 months (range, 5.9-194.7 months).

RESULTS:

Twenty-nine patients (17%) developed RN at a median time of 5 months (range, 1-26 months), 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 patients (11%) developed WMLs at a median time of 14.5 months (range, 2-62 months), most of them (n = 13; 72%) being asymptomatic (grade 1). White matter lesion grade 2 and 3 toxicities occurred in 4 and 1 patient(s), respectively. The 5-year RN-free and WML-free survival was 83% and 87%, respectively. In univariate analysis, neoadjuvant (P = .025) or any (P = .03) chemotherapy, hydrocephalus before PT (P = .035), and ependymoma (P = .026) histology were significant predictors of RN.

CONCLUSIONS:

Children treated with PT demonstrated a low prevalence of symptomatic RN (7%) or WML (3%) compared with similar cohorts treated with either proton or photon radiation therapy. Chemotherapy, ependymomal tumors and hydrocephalus as an initial symptom were significant risk factors for RN.

• Authors: Beat Bojaxhiu, Frank Ahlhelm, Marc Walser, Lorenzo Placidi, Ulrike Kliebsch, Lorentzos Mikroutsikos, Petra Morach, Alessandra Bolsi, Tony Lomax, Alessia Pica, Damien C Weber
• Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys) Vol. 100 Issue 4 Pg. 987-996 (03 15 2018) ISSN: 1879-355X [Electronic] United States
• PMID: 29485079 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2017 Elsevier Inc. All rights reserved.

Topics

• Adolescent
• Analysis of Variance
• Asymptomatic Diseases
• Brain (diagnostic imaging, pathology, radiation effects)
• Brain Neoplasms (diagnostic imaging, pathology, radiotherapy)
• Cerebellar Neoplasms (complications, pathology)
• Child
• Child, Preschool
• Ependymoma (complications, pathology)
• Female
• Humans
• Hydrocephalus (complications)
• Infant
• Magnetic Resonance Imaging
• Male
• Necrosis (diagnostic imaging, etiology, pathology)
• Proton Therapy (adverse effects, methods)
• Radiation Injuries (diagnostic imaging, pathology)
• Relative Biological Effectiveness
• Retrospective Studies
• Risk Factors
• White Matter (diagnostic imaging, pathology, radiation effects)