Utility of Long-Term Surveillance Neuroimaging Five Years Post-Diagnosis in the Management of Pediatric Brain Tumours

Research Article

Austin Pediatr Oncol. 2016; 1(1): 1002.

Utility of Long-Term Surveillance Neuroimaging Five Years Post-Diagnosis in the Management of Pediatric Brain Tumours

Hirpara DH¹, Bhatt MD² and Katrin S²*

¹Department of Medicine, University of Toronto, Canada

²Department of Pediatrics, McMaster Children’s Hospital and McMaster University, Canada

*Corresponding author: Scheinemann Katrin, Division of Pediatric Hematology/Oncology, Department of Pediatrics, McMaster Children’s Hospital and McMaster University, Canada

Received: February 20, 2016; Accepted: March 10, 2016; Published: March 19, 2016

Abstract

There is significant variability in surveillance imaging of Central Nervous System (CNS) tumours. We aimed to assess the utility of surveillance neuroimaging after five years from diagnosis in children with Low-Grade Glioma (LGG), Medulloblastoma (MB), Primitive Neuroectodermal Tumour (PNET) and Ependymoma (EP). A retrospective chart review was conducted of all eligible patients (0-18 years) between January 1, 1990 - December 31, 2006 followed at a major pediatric teaching hospital for at least five years. 94 patients were eligible for analysis. 13 relapses were detected over a span of 17 years (1993-2010). The median time to relapse post treatment was 3.2 ± 1.7 years (range: 0.5-13 years) and all relapses were among LGG patients. Two (15.4% of relapses) patients progressed after a period of five years from diagnosis; both were detected clinically. Of the 11 patients diagnosed with vascular abnormalities, nine (82%) had radiation-induced Cavernous Malformations (CM). The latency interval between radiation treatment and the detection of CM was 13.4 ± 4.2 years (range: 2-22 years). 67% of patients with CM had an underlying diagnosis of MB/PNET. Although there is a need for a larger prospective study, these findings serve as preliminary evidence to question the utility of routine surveillance neuroimaging in LGG patients beyond five years from diagnosis.

Keywords: Surveillance neuroimaging; Relapse; Low-grade glioma; Medulloblastoma; Ependymoma

Abbreviations

CNS: Central Nervous System; LGG: Low-Grade Glioma; MB: Medulloblastoma; PNET: Primitive Neuroectodermal Tumour; EP: Ependymoma; CM: Cavernous Malformations; MRI: Magnetic Resonance Imaging; CT: Computed Tomography

Introduction

The incidence of Central Nervous System (CNS) tumours is second only to leukemia in children. CNS tumours currently account for 19% of childhood cancer cases in Canada [1]. According to a Central Brain Tumour Registry of United States report, approximately 4150 people under the age of 20 were expected to develop a CNS tumor in the USA in 2012. The prevalence of primary CNS tumors in children (0- 19 years) is estimated to be 35.4 per 100,000; meaning over 28,000 children are living with this diagnosis in the USA [2].

Recent advances in the management of childhood CNS tumours have led to improved survival rates. The increase in life expectancy among survivors poses additional challenges such as optimal monitoring for relapses and long-term effects of treatment. Relapse is a major cause of death in children with certain types of CNS tumors [3-4]. As a result, monitoring for clinical symptoms and asymptomatic radiologic changes comprise essential elements of follow-up. Most treatment protocols and guidelines, however, discuss recommendations for clinical and radiologic follow-up only up to five years from diagnosis. There is significant variability in follow-up practices after five years, especially with surveillance neuroimaging. It is center dependent and ranges from yearly neuroimaging to quinquennial neuroimaging (once every five years). In our center, for instance, patients within five years of diagnosis undergo surveillance neuroimaging as per protocol. If there are no further recommendations, they are imaged biennially up to 10 years from diagnosis and quinquennially thereafter. However, there is no evidence to suggest an optimal approach.

The purpose of this study was to assess the utility of surveillance neuroimaging after five years from diagnosis in children diagnosed with Low-Grade Glioma (LGG), Medulloblastoma (MB), Primitive Neuroectodermal Tumour (PNET) and Ependymoma (EP). We reviewed children with these CNS tumours who were diagnosed, treated and followed at our institution to delineate the timing and identification of relapses and vascular abnormalities after a period of five years from diagnosis.

Materials and Methods

The study was approved by the local institutional review board. A retrospective chart review was conducted of all eligible patients: pediatric patients (0-18 years) diagnosed with LGG, MB, PNET and EP and followed at McMaster Children’s Hospital, Hamilton, Ontario, Canada. Our cohort consisted of patients diagnosed between January 1, 1990 and December 31, 2006. All patients were identified via clinic charts and hospital records. Patient’s clinical information, including their age at diagnosis, treatment regimen, age at relapse and incidence of secondary malignancies as well as surveillance neuroimaging data were collected to identify the frequency and detection of recurrences and vascular abnormalities.

Recurrence was defined as development of a new lesion at local or distant sites. Progression for LGGs was defined as 25% increase in size over two follow-up scans. For other tumors, it was defined as enlargement of the residual lesion in all three dimensions according to the Response Assessment in Neuro-Oncology (RANO) criteria [5]. This information was obtained retrospectively via reports written by a staff radiologist. Recurrences, progressions and vascular abnormalities were also classified by mode of detection: radiographic (i.e. asymptomatic) or clinical (i.e. symptomatic). A diagnosis of relapse or vascular abnormality was deemed clinical if symptoms (eg, change in ophthalmologic, endocrinologic, or neurologic status) preceded or prompted a neuroimaging study (MRI or CT). A diagnosis was deemed radiologic if detected in an asymptomatic patient undergoing a routine follow-up study.

Results

During the study period, a total of 110 pediatric patients were diagnosed with LGG, MB, PNET and EP. Of these, 16 patients were excluded for loss to follow-up before reaching five years postdiagnosis or for missing records. Data on 94 patients was obtained and analyzed. LGG patients accounted for 82% of the cohort (N=77) (Figure 1).

Citation: Hirpara DH, Bhatt MD and Katrin S. Utility of Long-Term Surveillance Neuroimaging Five Years Post- Diagnosis in the Management of Pediatric Brain Tumours. Austin Pediatr Oncol. 2016; 1(1): 1002.