Impact of WHO 2016 update of brain tumor classification, molecular markers and clinical outcomes in pleomorphic xanthoastrocytoma

Abstract

We present outcomes of pleomorphic xanthoastrocytoma (PXA) and correlate the impact of clinical, pathologic and molecular markers. Between 2006 and 2016, 37 patients with histologically verified PXA form the study cohort. All underwent maximal safe resection; those who had good resection and young age were observed. Adjuvant radiotherapy was given in patients with some atypical features such as high MIB-1 index (> 5%), residual disease or at recurrence. Patients with anaplastic PXA were administered adjuvant radiotherapy and systemic therapy. Median age at diagnosis was 20 years (range 4–45). At median follow-up of 33 months, 3-year and 5-year overall survival (OS) was 80.2 and 74% respectively. Patients who underwent GTR (23 cases, 62%) had significantly better 3-year PFS of 85.6% compared to 32.3% (p = 0.001) achieved with STR (13 cases, 35%). PFS was significantly superior in PXA grade II as compared to anaplastic PXA group (3-year estimates 80.2 vs. 32%; p = 0.007). 13 out of 27 patients where BRAFV600E testing was successful showed a mutation (48%). 3-year PFS and OS survival in BRAFV600E mutated patients was 51.9 and 76.9% compared to 73 and 75% in BRAFV600E non-mutated patients, respectively. No patient had IDH1 mutation. This data may provide valuable insights and act as a benchmark for future studies.

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