Management and outcome of focal low-grade brainstem tumors in pediatric patients: the St. Jude experience

Abstract

Object: Whereas diffuse intrinsic pontine gliomas generally have a short symptom duration and more cranial nerve involvement, focal brainstem gliomas are commonly low grade, with fewer cranial neuropathies. Although these phenotypic distinctions are not absolute predictors of outcome, they do demonstrate correlation in most cases. Because there is a limited literature on focal brainstem gliomas in pediatric patients, the objective of this paper was to report the management and outcome of these tumors.

Methods: The authors reviewed the records of all children diagnosed with radiographically confirmed low-grade focal brainstem gliomas from 1986 to 2010. Each patient underwent biopsy or resection for tissue diagnosis. Event-free survival (EFS) and overall survival were evaluated. Univariate analysis was conducted to identify demographic and treatment variables that may affect EFS.

Results: Fifty-two patients (20 girls, 32 boys) with follow-up data were identified. Median follow-up was 10.0 years, and the median age at diagnosis was 6.5 years (range 1-17 years). The tumor locations were midbrain (n = 22, 42%), pons (n = 15, 29%), and medulla (n = 15, 29%). Surgical extirpation was the primary treatment in 25 patients (48%). The 5- and 10-year EFS and overall survival were 59%/98% and 52%/90%, respectively. An event or treatment failure occurred in 24 patients (46%), including 5 deaths. Median time to treatment failure was 3.4 years. Disease progression in the other 19 patients transpired within 25.1 months of diagnosis. Thirteen of these patients received radiation, including 11 within 2 months of primary treatment failure. Although children with intrinsic tumors had slightly better EFS at 5 years compared with those with exophytic tumors (p = 0.054), this difference was not significant at 10 years (p = 0.147). No other variables were predictive of EFS.

Conclusions: Surgery suffices in many children with low-grade focal brainstem gliomas. Radiation treatment is often reserved for disease progression but offers comparable disease control following biopsy. In the authors' experience, combining an assessment of clinical course, imaging, and tumor biopsy yields a reasonable model for managing children with focal brainstem tumors.

Figure 1

Survival curves for EFS and overall survival for the entire study population (A), and EFS curves for intrinsic versus exophytic tumors (B), WHO Grade I versus Grade II tumors (C), mode of treatment (D), and extent of resection (E). RT = radiation therapy.

Figure 2

Images obtained in a 17-year-old boy who presented with medullary WHO Grade II astrocytoma. Three separate time points are selected for demonstration. A and B: Preoperative fractional anisotropy grayscale and color maps showing baseline imaging. C and D: Preoperative sagittal T1-weighted noncontrast (C) and T2-weighted MR images (D). E and F: Postoperative, preirradiation sagittal T1-weighted MR image obtained after contrast administration (E) and coronal T2-weighted MR image (F) obtained 1 week later. G and H: Postirradiation sagittal (G) and coronal (H) T1-weighted MR images obtained after contrast administration 21 months later.

Figure 3

Images obtained in a 10-year-old boy who presented with a mesencephalic WHO Grade I pilocytic astrocytoma. A–E: Preoperative images included sagittal T1-weighted noncontrast MR image (A), coronal T2-weighted FLAIR (B), diffusion tensor image of bilateral corticospinal tract (blue) with ipsilateral tract thinning (C), coronal fractional anisotropy (D), and coronal color map (E). F–J: Postoperative images, obtained 4 years after the preoperative images, included sagittal T1-weighted postcontrast (F), coronal T1-weighted postcontrast (G), diffusion tensor image of bilateral corticospinal tracts (blue) demonstrating recovery of ipsilateral tract thickness (H), coronal fractional anisotropy (I), and coronal color map (J).