Introduction: Pleomorphic Xanthoastrocytoma (PXA) is a rare primary low-grade astrocytic tumor with typically favorable prognosis [1,2]. However, these tumors can undergo malignant progression and rare reports of anaplastic PXA frequently describe frontal lobe location . Our objective was to characterize frontal lobe PXA relative to similar tumors located in other anatomical regions.
Methods: We queried the the Surveillance, Epidemiology, and End Results (SEER) database from 1973-2014 for cases of PXA as coded by ICD-O-3 and subdivided histologically-verified cases (N=447) into two groups by location: frontal lobe (N=89) and all others (N=358). To compare these groups, we utilized Chi-square test, Student’s T-test and Kruskall-Wallis test as appropriate. We performed Kaplan Meier survival analysis followed by Cox proportional hazards regression analysis to adjust for confounding factors related to survival.
Results: Frontal lobe PXA were significantly enriched in higher (anaplastic/dedifferentiated) grade (28.1%_vs._11.6%, P=0.007) and were diagnosed at a later age (33yrs_vs._25.8yrs, P=0.0007) as compared to PXA in other locations. Patients with frontal lobe tumors were more likely to have surgery+adjuvant radiation/chemotherapy treatment (42.7%_vs._19.0%, P< 0.001) and less likely to undergo surgical resection only (48.3%_vs._64.8%, P=0.006). Unadjusted median survival from diagnosis was significantly lower in frontal lobe (38 months) versus other locations PXA (62 months) (P=0.026). On multivariate analysis, increased age (HR 1.0372 (1.0246-1.0500), P<0.0001), anaplastic/dedifferentiated grade (HR 1.7911 (1.0345-3.1009), P=0.0374), and tumor size (HR 1.7065 (1.0226-2.8477), P=0.0408), but not specific tumor location itself, were found to be significant predictors of adjusted mortality. Exclusively surgical resection (HR 0.2663 (0.0974-0.7279), P=0.0099) and gross total resection (HR 0.4877 (0.2951-0.8061), P=0.0051) of tumor predicted improved survival.
Conclusions: Frontal lobe PXA location is significantly associated with clinically aggressive features that predict decreased survival and require more complex treatment. These findings have important implications in prognostication and management of these tumors and warrant further investigation into underlying causes.
Patient Care: Pleomorphic Xanthoastrocytoma (PXA) is a rare primary low-grade astrocytic tumor, which typically arises in the temporal lobe and is associated with a favorable prognosis. However, our data suggest that frontal lobe location of these tumors is predictive of increased mortality due to its association with certain clinically aggressive features, including enrichment in anaplastic/dedifferentiated grade and older age at presentation. These findings should be taken into consideration for prognostication and treatment planning to improve patient outcomes. In addition, our study is an important contribution to the clinical characterization of PXA and warrants further investigation into underlying causes of the differences that we have observed.
Learning Objectives: By the conclusion of this session, participants should be able to:
1. Characterize epidemiology and distinct clinical features of frontal lobe PXA.
2. Appreciate significant differences in clinical characteristics and outcomes between frontal lobe PXA and PXA arising in other anatomical locations.
3. Determine prognostic factors associated with survival in patients with PXA.
References: 1. Perkins SM, Mitra N, Fei W, Shinohara ET. Patterns of care and outcomes of patients with pleomorphic xanthoastrocytoma: A SEER analysis. J Neurooncol. 2012;110:99–104.
2. Ida CM, Rodriguez FJ, Burger PC, Caron AA, Jenkins SM, Spears GM, Aranguren DL, Lachance DH, Giannini C. Pleomorphic Xanthoastrocytoma: natural history and long-term follow-up. Brain Pathology. 2015;25:575–586.
3. Marton E, Feletti A, Orvieto E, Longatti P. Malignant progression in pleomorphic xanthoastrocytoma: personal experience and review of the literature. J Neurol Sci. 2007;252:144–53.