Clinical and Molecular Characteristics and Outcome of Adult Medulloblastoma at a Tertiary Cancer Center

<b>Background/Objectives</b>: Adult medulloblastoma is a rare entity, with management data extrapolated from pediatric medulloblastoma cases. We aim to report the clinical characteristics, prognostic factors, and treatment outcome of a cohort of adult patients with medulloblastoma. <b>Methods</b>: Fifty-three patients aged ≥ 18 years with medulloblastoma treated at King Hussein Cancer Center between 2007 and 2019 were retrospectively reviewed. Patients' diseases were staged according to modified Chang's staging system. All patients received adjuvant craniospinal irradiation followed by a posterior fossa boost. Baseline disease characteristics, including molecular subgrouping, were tested as prognostic factors of progression-free survival (PFS) and overall survival (OS) by using univariate analysis. <b>Results</b>: Median follow-up was 70 months (range 37.5-104.5 months). Twenty-two tumors were of the SHH-activated subtype. Conversely, WNT-activated and group 4 tumors had three cases each. Only 37.7% of patients died. The mean 3-year, 5-year, and 10-year OS were 85% (75-95%), 74% (62-87%), and 50% (33-75%), respectively. Significant differences in OS were associated with the extent of surgery (<i>p</i> = 0.017), M stage (<i>p</i> = 0.009), and risk status (<i>p</i> < 0.001). Relapses were detected in 28.3% of cases. The 3-year, 5-year, and 10-year PFS were 81% (71-92%), 75% (63-88%), and 66% (52-83%), respectively. Significant differences in PFS were associated with the extent of surgery (<i>p</i> = 0.008) and risk status (<i>p</i> = 0.012). Molecular subgrouping did not correlate with OS or PFS. <b>Conclusions</b>: Our results revealed poor survival of patients with high-risk disease, which may necessitate the intensification of chemotherapy. Molecular subgrouping did not correlate with the outcome in this cohort.