Imaging Changes in Pediatric Intracranial Ependymoma Patients Treated With Proton Beam Radiation Therapy Compared to Intensity Modulated Radiation Therapy.
OBJECTIVE
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
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.
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Jillian R
JR
Gunther
Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children's Cancer Center, Houston, Texas.
Mariko
M
Sato
Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children's Cancer Center, Houston, Texas.
Murali
M
Chintagumpala
Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Leena
L
Ketonen
Department of Pediatric Radiology, Texas Children's Hospital, Houston, Texas.
Jeremy Y
JY
Jones
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Pamela K
PK
Allen
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children's Cancer Center, Houston, Texas.
Arnold C
AC
Paulino
Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children's Cancer Center, Houston, Texas.
M Fatih
MF
Okcu
Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children's Cancer Center, Houston, Texas.
Jack M
JM
Su
Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Jeffrey
J
Weinberg
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Nicholas S
NS
Boehling
Department of Pediatrics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Soumen
S
Khatua
Department of Pathology, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas.
Adekunle
A
Adesina
Department of Neurosurgery, Texas Children's Hospital, Houston, Texas.
Robert
R
Dauser
Department of Neurosurgery, Texas Children's Hospital, Houston, Texas.
William E
WE
Whitehead
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. Electronic address: amahajan@mdanderson.org.
Anita
A
Mahajan
D000293:Adolescent; D000367:Age Factors; D000704:Analysis of Variance; D001921:Brain / Q000528:radiation effects*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D001933:Brain Stem / Q000000981:diagnostic imaging / Q000528:radiation effects; D002648:Child; D002675:Child, Preschool; D004806:Ependymoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D016017:Odds Ratio; D061766:Proton Therapy / Q000009:adverse effects / Q000379:methods*; D011832:Radiation Injuries / Q000000981:diagnostic imaging / Q000188:drug therapy; D011859:Radiography; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D012307:Risk Factors