Low rates of recurrence and slow progression of pediatric pilocytic astrocytoma after gross-total resection: justification for reducing surveillance imaging

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>Pilocytic astrocytomas (PAs) are common brain tumors in children. Optimal management of PA is gross-total resection (GTR), after which event-free survival (EFS) is excellent. The tempo of recurrences, when they do occur, is relatively sparsely reported, and there is no agreed upon surveillance recommendation for patients in this category. It has been suggested that surveillance MRI is performed too frequently and could be safely reduced in both frequency and duration. The authors conducted a retrospective review of pediatric patients with PA who underwent GTR at a single institution over an 18-year period and who had documented recurrences.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>All patients under 18 years of age who had undergone GTR of a PA between 1996 and 2013 were included in the study. Clinical, radiological, and tumor characteristics were recorded.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>Sixty-seven patients met the criteria for GTR over the period studied. The 5-year EFS rate was 95% (95% CI 89%–100%) and overall survival was 100%. Recurrences showed a nonsignificant trend of occurring more commonly in patients with persistent nonenhancing FLAIR abnormalities after surgery, but there was no difference with regard to tumor location. All recurrences occurred before 3 years postresection, all were asymptomatic, and all patients were observed for at least one additional scan after the initial detection during routine surveillance MRI before further therapy was undertaken.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>EFS and overall survival are excellent after GTR in this population with PAs. Progression after recurrence occurs slowly and is asymptomatic. A less intensive schedule of MRI surveillance in this group of patients would result in time and cost savings, without compromising safety. The authors suggest a schedule of 6 MRI scans to be obtained postoperatively, at 3–6 months, then at 1, 2, 3.5, and 5 years.</jats:p></jats:sec>

Heterogeneity of histopathological presentation of pilocytic astrocytoma – diagnostic pitfalls. A review

“…Total or even subtotal removal is an effective treatment in cerebellar and superficial cerebral pilocytic tumours [29]. The long-term functional outcome is generally favourable, in the absence of post-operative complications and brain stem involvement [2].…”

“…The vast majority of cases are associated with benign clinical behaviour and a favourable long-term outcome, particularly those of cerebellar location and complete surgical resection [27][28][29]60]. However, some tumours, despite their benign histology, may behave more aggressively.…”

Methylation profiling of paediatric pilocytic astrocytoma reveals variants specifically associated with tumour location and predictive of recurrence

“…An important aspect in the treatment of paediatric PA is managing tumour recurrence, associated with extracerebellar tumour location, subtotal surgical resection and poorer outcomes (Armstrong et al ., ; Bandopadhayay et al ., ; Collins et al ., ; Dodgshun et al ., ; Fernandez et al ., ; Krishnatry et al ., ; Lund et al ., ; Ohgaki and Kleihues, ; Youland et al ., ). At present, there are limited data related to the molecular features underpinning this behaviour.…”

“…This was not apparent in control tissue (normal cortex); therefore, it is unlikely to be a technical artefact and is consistent with dysregulation of expression of NR2E1 in PA. These contrasting findings require further investigation in order to better understand the role of NR2E1 in the development of PA. An important aspect in the treatment of paediatric PA is managing tumour recurrence, associated with extracerebellar tumour location, subtotal surgical resection and poorer outcomes (Armstrong et al, 2009;Bandopadhayay et al, 2014;Collins et al, 2015;Dodgshun et al, 2016;Fernandez et al, 2003;Krishnatry et al, 2016;Lund et al, 2011;Ohgaki and Kleihues, 2005;Youland et al, 2013). At present, there are limited data related to the molecular features underpinning this behaviour.…”

“…In contrast, sporadic PAs arise most commonly in the cerebellum, followed by the supratentorial region, optic pathway and hypothalamus, brainstem and spinal cord (Burkhard et al, 2003;Collins et al, 2015). PAs grow slowly and rarely transform to higher grades or metastasise (Collins et al, 2015); however, the possibility of local recurrence remains (particularly after incomplete surgical resection) (Dodgshun et al, 2016;Gnekow et al, 2012;Youland et al, 2013). PA in childhood has an excellent prognosis, with a 10-year overall survival rate of over 90% (Bandopadhayay et al, 2014;Collins et al, 2015;Ohgaki and Kleihues, 2005); however, age (< 2 years), location (extracerebellar) and incomplete resection are associated with poorer outcome (Bandopadhayay et al, 2014;Collins et al, 2015).…”