Novel Surgical and Radiologic Risk Factors for Progression or Recurrence of Pediatric Pilocytic Astrocytoma

Abstract

<b><i>Introduction:</i></b> Pilocytic astrocytomas (PA) are a common, benign childhood tumor known for their slow growth rates and excellent prognosis. The aim of our study was to characterize patient, tumor, and imaging-related risk factors for recurrence and progression of disease. <b><i>Methods:</i></b> We identified 116 patients with PA who underwent surgery at our institution between 2000 and 2015. Data were collected retrospectively from the clinical charts. <b><i>Results:</i></b> The mean age at resection was 7 ± 5 years (range 0.5–31) and mean follow-up was 6 ± 3 years. Initial resection was complete in 33 patients (29%), subtotal in 78 patients (67%), and biopsy in 5 patients (4%). A total of 45/116 (40%) patients experienced either recurrence or progression after initial resection with a mean time to recurrence or progression of 2.2 years. Bivariate analysis identified subtotal resection, tumor location, age at diagnosis, and imaging features (i.e., T2 invasion, exophytic component, hemorrhage, and solid tumors) as factors significantly associated with recurrence or progression (<i>p</i> < 0.05). Conversely, PAs that were completely resected, predominately cystic, and located in the cerebellum were significantly associated with no recurrence or progression (<i>p</i> < 0.05). Multivariate regression analysis narrowed down 4 robust risk factors: extent of resection, T2 invasion, predominantly solid lesions, and presence of an exophytic component (<i>p</i> < 0.05). <b><i>Conclusion:</i></b> Total surgical removal of PA has been the most important prognostic factor for the clinical course of PA. Our study reveals additional risk factors for the recurrence or progression of disease: tumor invasion, solid composition, and tumors with an exophytic component.

Meta‐Analysis of Apparent Diffusion Coefficient in Pediatric Medulloblastoma, Ependymoma, and Pilocytic Astrocytoma

“…Ependymoma, which is a very “surgical” tumor, has a prognosis, which is heavily dependent on completeness of resection 6 . Conversely in Pilocytic astrocytoma, which can sometimes be a very infiltrative entity, tumor may be intentionally left behind due to its location and anticipated relatively benign course 7 . Similarly, tumors suspected of being medulloblastomas may be intentionally sub‐totally resected due to concerns of a high risk of causing a posterior fossa syndrome by aggressively chasing invasive tumor in the cerebellar peduncles when that tumor may subsequently be very responsive to adjuvant postoperative therapies 8 .…”

“…6 Conversely in Pilocytic astrocytoma, which can sometimes be a very infiltrative entity, tumor may be intentionally left behind due to its location and anticipated relatively benign course. 7 Similarly, tumors suspected of being medulloblastomas may be intentionally sub-totally resected due to concerns of a high risk of causing a posterior fossa syndrome by aggressively chasing invasive tumor in the cerebellar peduncles when that tumor may subsequently be very responsive to adjuvant postoperative therapies. 8 The surgical strategy does then vary considerably between these three commonest entities, and it would be extremely useful for surgeons to have a reliable indication of diagnosis while they are planning and carrying out surgery.…”

Long-term outcome after management of pilocytic astrocytoma in the posterior fossa in a pediatric population

“…Abundant evidence shows a strong correlation between tumor progression as well as recurrence, with neurological functional outcome in pediatric patients suffering from PA ( Villanueva et al, 2019 , Park et al, 2019 , Fernandez et al, 2003 , Bernhardtsen et al, 2003 , Hayostek et al, 1993 ). Therefore, numerous studies have investigated possible predictors influencing tumor progression or recurrence.…”

“…Pilocytic astrocytoma (PA) in the posterior fossa is one of the most common tumor entities in pediatric patients although the overall incidence in the whole population remains low ( Villanueva et al, 2019 , Donofrio et al, 2020 , Rickert and Paulus, 2001 ). The current standard of care for such lesions is surgery with maximal extent of resection, sometimes followed by radiotherapy in case of incomplete resection and recurrent tumor growth ( Villanueva et al, 2019 , Park et al, 2019 , Palma et al, 2004 ).…”

“…Pilocytic astrocytoma (PA) in the posterior fossa is one of the most common tumor entities in pediatric patients although the overall incidence in the whole population remains low ( Villanueva et al, 2019 , Donofrio et al, 2020 , Rickert and Paulus, 2001 ). The current standard of care for such lesions is surgery with maximal extent of resection, sometimes followed by radiotherapy in case of incomplete resection and recurrent tumor growth ( Villanueva et al, 2019 , Park et al, 2019 , Palma et al, 2004 ). Being a benign glial tumor (WHO grade I), the 5-year survival rate for PA in general is estimated to be ≈ 97% ( Segal and Karajannis, 2016 ), which is highly influenced by the extent of surgical resection ( Park et al, 2019 , Fernandez et al, 2003 ).…”