Extent of resection predicts risk of progression in adult pilocytic astrocytoma.

Object: Pilocytic astrocytomas are rare tumours in adults. Presentation, management and prognostic factors are poorly characterised. Methods: Retrospective single centre study from 2000 to 2016. Results: 50 cases were identified (median age 29 years; range 16-76). Symptoms at presentation were neurological deficit (n = 21), headache (n = 18) and seizures (n = 6). Five were incidental findings. Five patients had hydrocephalus at presentation and required emergent management, two by endoscopic third ventriculostomy and three by external ventricular drain. Symptoms were present for a median of 16 weeks (range 1 week to 34 years). Surgery consisted of gross total resection (n = 23), subtotal resection (n = 21) or biopsy (n = 6). Progression occurred in 20 patients at a median time of 7 years following surgery and was asymptomatic in just over half of these cases. A greater degree of resection (complete vs. subtotal) was associated with longer time to progression (Kaplan-Meier analysis, log rank test = 3.58, p = 0.059). At their first progression 12 patients underwent re-resective surgery and the remainder received radiotherapy. The median 5-year survival was 80%. Conclusions: In adult patients with a pilocytic astrocytoma, a macroscopic resection should be the aim at the first resective operation. Emergency management of hydrocephalus may be required in the first instance.