Imaging Changes in Pediatric Intracranial Ependymoma Patients Treated With Proton Beam Radiation Therapy Compared to Intensity Modulated Radiation Therapy.

Abstract

PURPOSE:

The clinical significance of magnetic resonance imaging (MRI) changes after radiation therapy (RT) in children with ependymoma is not well defined. We compared imaging changes following proton beam radiation therapy (PBRT) to those after photon-based intensity modulated RT (IMRT).

METHODS AND MATERIALS:

Seventy-two patients with nonmetastatic intracranial ependymoma who received postoperative RT (37 PBRT, 35 IMRT) were analyzed retrospectively. MRI images were reviewed by 2 neuroradiologists.

RESULTS:

Sixteen PBRT patients (43%) developed postradiation MRI changes at 3.8 months (median) with resolution by 6.1 months. Six IMRT patients (17%) developed changes at 5.3 months (median) with 8.3 months to resolution. Mean age at radiation was 4.4 and 6.9 years for PBRT and IMRT, respectively (P = .06). Age at diagnosis (>3 years) and time of radiation (≥3 years) was associated with fewer imaging changes on univariate analysis (odds ratio [OR]: 0.35, P = .048; OR: 0.36, P = .05). PBRT (compared to IMRT) was associated with more frequent imaging changes, both on univariate (OR: 3.68, P = .019) and multivariate (OR: 3.89, P = .024) analyses. Seven (3 IMRT, 4 PBRT) of 22 patients with changes had symptoms requiring intervention. Most patients were treated with steroids; some PBRT patients also received bevacizumab and hyperbaric oxygen therapy. None of the IMRT patients had lasting deficits, but 2 patients died from recurrent disease. Three PBRT patients had persistent neurological deficits, and 1 child died secondarily to complications from radiation necrosis.

CONCLUSIONS:

Postradiation MRI changes are more common with PBRT and in patients less than 3 years of age at diagnosis and treatment. It is difficult to predict causes for development of imaging changes that progress to clinical significance. These changes are usually self-limiting, but some require medical intervention, especially those involving the brainstem.

• Authors: Jillian R Gunther, Mariko Sato, Murali Chintagumpala, Leena Ketonen, Jeremy Y Jones, Pamela K Allen, Arnold C Paulino, M Fatih Okcu, Jack M Su, Jeffrey Weinberg, Nicholas S Boehling, Soumen Khatua, Adekunle Adesina, Robert Dauser, William E Whitehead, Anita Mahajan
• Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys) Vol. 93 Issue 1 Pg. 54-63 (Sep 01 2015) ISSN: 1879-355X [Electronic] United States
• PMID: 26279024 (Publication Type: Comparative Study, Journal Article, Multicenter Study, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2015 Elsevier Inc. All rights reserved.

Topics

• Adolescent
• Age Factors
• Analysis of Variance
• Brain (radiation effects)
• Brain Neoplasms (diagnostic imaging, pathology, radiotherapy)
• Brain Stem (diagnostic imaging, radiation effects)
• Child
• Child, Preschool
• Ependymoma (diagnostic imaging, pathology, radiotherapy)
• Female
• Humans
• Infant
• Magnetic Resonance Imaging
• Male
• Odds Ratio
• Proton Therapy (adverse effects, methods)
• Radiation Injuries (diagnostic imaging, drug therapy)
• Radiography
• Radiotherapy, Intensity-Modulated (adverse effects, methods)
• Retrospective Studies
• Risk Factors