Children with supratentorial midline pilocytic astrocytomas exhibit multiple progressions and acquisition of neurologic deficits over time

Pilocytic astrocytomas (PAs) are the most common brain tumors of childhood1 and can arise anywhere within the neuroaxis, including the posterior fossa (pf-PA), supratentorial midline (sm-PA; including optic pathway, hypothalamus, thalamus), supratentorial cortex (sc-PA), brainstem (bs-PA), and spinal cord (sp-PA). While tumor location (sm, bs) has been proposed as a prognostic factor associated with poor progression-free survival (PFS),2-4 this effect is abrogated when resection status (gross total resection [GTR], subtotal resection [STR]) is included.2,4 To determine whether tumor location has any value in predicting PA clinical outcome, we evaluated clinical outcomes of children with biopsy-proven PA treated at St. Louis Children's Hospital between 2003 and 2021 (n = 251). Subjects with a diagnosis of neurofibromatosis type 1 (NF1; n = 13) and those with discrepancies in their pathologic diagnosis (n = 11) or missing pertinent clinical data (n = 36) were excluded, leaving 191 total subjects for analysis. Consistent with prior reports,5 children with sc-PA were typically older at diagnosis than those with pf-PA. There were no differences in PA location incidence by sex,1 but individuals with sm-PA and bs-PA had higher rates of STR (Figure 1A) and reduced PFS (Figure 1B).2,3 Importantly, this difference in PFS was related to resection status, such that longer PFS was observed in sm-JPA and bs-JPA cases in which a GTR was achieved (Figure 1C).