The role of surveillance magnetic resonance imaging (MRI) scanning in detecting recurrent brain tumors in asymptomatic children

Background There is controversy regarding the utility of routine surveillance scanning for asymptomatic children with brain tumors. Although the role of CT or magnetic resonance imaging (MRI) scanning in this setting has been examined in several studies, none have focused on children followed exclusively by MRI. The purpose of this study was to determine how often recurrent brain tumors are detected by routine MRI surveillance in asymptomatic children. Methods The medical records of all children with brain tumors treated at Children's Hospital at Strong from 1990-1999 were reviewed. Recurrence was defined as an increase in size of the tumor on MRI scan. Astrocytomas and gangliogliomas were classified as low-grade tumors; high-grade astrocytomas, medulloblastomas, and ependymomas were classified as high-grade tumors. Results Of the 112 evaluable children with brain tumors during this time period, 46 (41%) suffered an MRI-documented recurrence. Of these 46 patients, 13 (28%) had low-grade tumors and 33 (72%) had high-grade tumors. Twenty-seven of the 46 recurrences (59%) occurred in asymptomatic children. Ten of the 13 children (77%) with recurrent low-grade tumors were asymptomatic compared to 17 of 33 children (52%) with recurrent high-grade tumors (p = 0.18). The median survival from time of recurrence for the symptomatic children was seven months, while the median survival from time of recurrence for the asymptomatic children has not yet been reached (p = 0.025). When the analysis was confined to children with high-grade tumors, there was no difference in median survival from the time of recurrence for symptomatic versus asymptomatic children (5 mo. versus 7 mo.) (p = 0.25). The frequency of detection of recurrences by surveillance scanning in asymptomatic children was 4.2% (one recurrence detected per 24 surveillence MRI scans). Conclusion The majority of recurrent brain tumors are detected by MRI surveillence in asymptomatic children. However, asymptomatic recurrences were detected in only a small proportion of surveillance scans and had no impact on survival in children with high-grade tumors.