Pediatric Patients With SHH Medulloblastoma Fail Differently as Compared With Adults: Possible Implications for Treatment Modifications.

ABSTRACT

PURPOSE: The purpose of this work was to study the diversity of sonic hedgehog (SHH) medulloblastoma across different age groups with an emphasis on patterns of relapse. METHODS: All data for the study were obtained through review of medical records, imaging, radiation charts, treatment planning, and chemotherapy details. RESULTS: Sixty-three patients with SHH medulloblastoma were identified from a prospectively maintained database and classified into 3 groups-infantile ≤3 years (i-SHH, n=11); pediatric >3 to <18 years (p-SHH, n=21); and adult ≥18 years (a-SHH; n=31). Lateralized tumors were common with increasing age (81% a-SHH, 67% p-SHH, 27% i-SHH; P=0.01). Large cell anaplastic histology was relatively common for p-SHH (33%), while the nodular/desmoplastic variant was more frequent in i-SHH (64%) and adults (51%). Median follow-up was 38 months (range, 5 to 91 mo). Five-year event-free survival was 80%, 31%, and 52% for i-SHH, p-SHH, and a-SHH, respectively (P=0.001). Median time to failure for p-SHH and a-SHH were 12 and 36 months, respectively. For p-SHH, 83% were metastatic relapses compared with localized failure in 75% for a-SHH. Five-year overall survival for i-SHH, p-SHH, and a-SHH were 91%, 31%, and 70%, respectively (P=0.001). On univariate analysis, event-free survival was significantly worse for superiorly located tumors (P=0.01), nondesmoplastic histology (P=0.02), and histology alone for overall survival (P=0.04) (none on multivariate analysis). CONCLUSIONS: SHH medulloblastoma demonstrates varied outcomes depending on age, with p-SHH associated with early and metastatic relapses, while for a-SHH it tends to be delayed and localized.