Bithalamic Involvement Predicts Poor Outcome among Children with Thalamic Glial Tumors

Abstract

Clinical features and treatment of 36 consecutive pediatric patients with thalamic glial tumors confirmed by histology and characterized by neuroimaging were reviewed to identify prognostic factors. The median age at diagnosis was 10 years (range 1–18 years). Twenty-four patients had low-grade tumors (juvenile pilocytic astrocytoma n = 9, fibrillary astrocytoma n = 6, astrocytomas not otherwise specified n = 6, ganglioglioma n = 2 and oligodendroglioma n = 1) and 12 patients had high-grade tumors (glioblastoma multiforme n = 7, anaplastic astrocytoma n = 4 and unclassified malignant tumor n = 1). With a median follow-up of 4.3 years among survivors, estimates of 4-year progression-free survival (PFS) and overall survival (OS) for the entire group are 28 ± 10 and 37 ± 10%, respectively. Low-grade tumors were associated with a significantly better 4-year PFS (36 ± 12 vs. 0% for the high-grade group; p = 0.03) and OS (52 ± 12 vs. 0%; p < 0.001). This review identified that bithalamic involvement, characterized by neuroimaging, exerted an independent and significant negative impact on PFS and OS for patients with low-grade tumors. Estimates of 4-year PFS and OS among patients with low-grade bithalamic versus monothalamic tumors were 58 ± 15 vs. 0% and 85 ± 11 vs. 0% (p < 0.00001), respectively. The presence of bithalamic involvement did not affect outcome among patients with high-grade tumors. Additionally, age at diagnosis, enhancement with neuroimaging contrast, extension beyond the thalamus and extent of surgical resection did not correlate with overall outcome. Because treatment approaches varied during the study period, the impact of radiation therapy or chemotherapy could not be assessed. This contemporary, single-institution series of pediatric thalamic glial tumors demonstrates, for the first time, the statistical significance of bithalamic involvement as a marker of poor prognosis among patients with low-grade glial lesions.

Initial Management of Children with Hypothalamic and Thalamic Tumors and the Modifying Role of Neurofibromatosis-1

“…Less than 1/3 of cases of thalamic astroglial tumors will behave like a low-grade glioma, and the prognosis for the majority of cases is not favorable. The overall 4-year survival for all cases with thalamic primary tumors is 37% [6]. NF-1 is distinctly uncommon is this population.…”

Pediatric Thalamic Gliomas: An Updated Review

“…Of these publications, 20 were case series (Table). 1,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Histologically, the vast majority (70%-90%) of reported thalamic tumors are classified as astrocytoma. However, this literature is limited and difficult to interpret regarding histologic subtypes in children, as many studies combine age groups, are confined to more specific entities (eg, pilocytic astrocytoma (PA) or ''high-grade astrocytoma''), group biologically distinct entities (eg, PA and low-grade diffuse astrocytoma [DA] as ''low-grade astrocytoma''), or are single case reports.…”

“…Interestingly, a number of authors have singled out thalamic or ''central'' oligodendroglioma as being biologically distinct both from diffuse thalamic astrocytomas of a comparable grade and from peripheral (hemispheric) pediatric oligodendrogliomas of a comparable grade. 6,7,11,16,26,39 Thalamic oligodendrogliomas are often anaplastic at biopsy/ resection and relentlessly progress (14% 3-year survival in one series) despite extent of resection or chemotherapy and radiation in a manner comparable with thalamic glioblastoma. 16 Surprisingly, low-grade (WHO grade II) thalamic oligodendrogliomas have a similarly dismal prognosis.…”

“…But with improved surgical techniques, total or partial resection is now more frequently performed, particularly for noninfiltrating, low-grade tumors. [1][2][3][4][5][6][7][8][9][10][11][12][13] Additionally, children with even incompletely resected low-grade thalamic gliomas can have a 5-year overall survival rate greater than 80% with adjuvant chemotherapy and radiation. 13,14 Therefore, histologic verification is now thought to be critical for planning treatment, and, as a result, biopsy and total/subtotal resections are much more common today than in the past.…”

Childhood Brain Tumors

“…Temozolomide + ABT-888 is currently being evaluated both in adults with malignant glioma and children with recurrent brain tumors. Children with midline HGG including those in the thalamus and diffuse intrinsic lesions within the brain stem (e.g., diffuse pontine glioma) are unresectable based on location and have a grave prognosis (Reardon, Gajjar et al 1998;Mandell, Kadota et al 1999). While patients with thalamic tumors undergo biopsy to confirm histology of HGG, it is no longer deemed necessary in patients with MRI findings of a diffuse intrinsic brain stem glioma.…”