Treatment Outcomes and Prognostic Factors for Patients With Medulloblastoma Having Defined Molecular Subtypes

This study aims to evaluate treatment outcomes and prognostic factors in pediatric patients with medulloblastoma (MB) with defined molecular subtypes to inform subsequent individualized treatment.

A retrospective analysis was conducted on 145 patients with MB with defined molecular subtypes who underwent radiation therapy (RT) at our institution from January 2017 to 2021. Patients were subjected to traditional clinical risk stratification, molecular risk stratification, and National Comprehensive Cancer Network (NCCN) risk stratification, respectively. The treatment outcomes and associated prognostic factors were analyzed.

With a median follow‑up of 49 months, the 5-year event-free survival (EFS) and overall survival rates were 68.6% ± 4.0% and 74.7% ± 4.4%, respectively. Multivariate analysis revealed that failure to achieve a complete response after RT (5-year EFS 39.3% ± 9.2% vs 75.7% ± 4.2%; P = .007), the administration of fewer than 6 cycles of chemotherapy (5-year EFS 25.0% ± 11.6% vs 73.9% ± 4.0%; P < .001), and categorization as a member of the NCCN high-risk group (5-year EFS 48.0% ± 6.5% vs 84.5% ± 4.2%; P = .040) were associated with a worse prognosis. Twenty (27.4%) clinical standard-risk patients were reclassified as low risk or high/very high risk according to the NCCN risk stratification with 5-year EFS rates of 100.0% ± 0.0% and 58.3% ± 16.1%, respectively. Further subgroup analysis (N = 103) revealed that patients with 1q gain (5-year EFS 32.7% ± 16.1% vs 67.0% ± 5.2%; P = .035), 10q loss (5-year EFS 25.0% ± 21.7% vs 69.6% ± 4.6%; P = .024), MYCN amplification (5-year EFS 40.0% ± 15.5% vs 70.8% ± 4.1%; P = .010) or TP53 mutation (5-year EFS 33.3% ± 13.6% vs 71.9% ± 4.0%; P = .002) had a worse EFS than those with wild type.

MB is a heterogeneous disease that requires the integration of clinical and molecular features for defined risk stratification to facilitate individualized treatment. In this study, we found that residual disease after RT, fewer than 6 cycles of chemotherapy, and high-risk NCCN risk stratification were independent adverse prognostic factors for patients with MB.