Surgery

Cerebellum: Complete or near-complete removal can be obtained in 90% to 95% of patients with pilocytic astrocytomas located in the cerebellum.[6]

Optic nerve: For children with isolated optic nerve lesions and progressive symptoms, complete surgical resection, while curative, generally results in blindness in the affected eye. In the absence of retained vision in the affected eye, complete surgical resection may be considered when cosmesis related to proptosis is of concern.

Midline structures (hypothalamus, thalamus, and brain stem): Circumscribed astrocytic gliomas located in midline structures can sometimes be aggressively resected, with resultant long-term disease control.[3] Despite the increasing surgical accessibility of these tumors, such resection may result in significant neurological sequelae, especially in children younger than 2 years at diagnosis.[7][Level of evidence C1] For pediatric-type diffuse low-grade gliomas in deep-seated lesions, extensive surgical resection may not be appropriate and biopsy only should be considered.[8][Level of evidence C2] In general, for focal brain stem gliomas, particularly those arising in the pons and medulla, maximal safe surgical resection is attempted.[9] While a greater extent of resection is associated with a higher progression-free survival (PFS), this must be balanced with the risk of new postsurgical complications. In a series of 116 patients with low-grade gliomas of the brain stem, 100 patients had some surgical intervention. Twenty-seven patients underwent a biopsy, only one of whom had new postoperative deficits. Seventy-three patients underwent a complete or partial resection, and almost 30% of this group had significant postoperative complications, including respiratory insufficiency (five patients), cerebellar mutism (three patients), and cranial nerve palsies or paresis (15 patients).[10]

Cerebrum: Hemispheric circumscribed astrocytic gliomas are often amenable to complete surgical resection.

Spine: Surgical resection of spinal tumors is generally attempted but it often cannot be completed. In a cohort of 128 patients with primary spinal cord low-grade gliomas, gross-total resection was achieved in a minority of the patients (24 of 128). For the entire cohort, long-term disease control was achieved in about 87% of patients, but subsequent treatment in the form of repeat resection, chemotherapy, and/or radiation therapy was frequently required. Notably, disease progression was common (51 of 128 patients), with late-progression events occurring often. Neurological sequelae and orthopedic complications were common.[11][Level of evidence C2]

Tumor location: Children with cerebellar and cerebral tumors showed a higher PFS rate at 8 years compared with patients with midline and chiasmatic tumors (84% ± 1.9% vs. 51% ± 5.9%, respectively).

Histology: Approximately three-fourths of patients had pilocytic astrocytoma; PFS and OS were superior for these patients when compared with children with nonpilocytic tumors.

Extent of resection: Patients with gross-total resection had 8-year PFS rates exceeding 90% and OS rates of 99%. By comparison, approximately one-half of patients with any degree of residual tumor (as assessed by operative report and by postoperative imaging) showed disease progression by 8 years, although OS rates exceeded 90%.[6] A multivariate analysis examined 100 patients with confirmed diagnoses of World Health Organization (WHO) grade 2 diffuse gliomas treated in an International Society of Paediatric Oncology (SIOP) study. The extent of glioma resection had the greatest impact on event-free survival (EFS) rates. The 5-year EFS rates were 75% to 76% for patients who underwent a complete or subtotal resection. In comparison, 5-year EFS rates were 56% for patients who had a partial resection and 19% for patients who had a biopsy.[14][Level of evidence B4]The extent of resection necessary for cure is unknown because patients with microscopic and even gross residual tumor after surgery may experience long-term PFS without postoperative therapy.[5,6]

Age: Younger children (age <5 years) showed higher rates of tumor progression but there was no significant age effect for OS in multivariate analysis. In a retrospective review of a different series of pediatric patients, children younger than 1 year with low-grade gliomas demonstrated an inferior PFS compared with children aged 1 year and older.[15]