Retrospective investigation of medulloblastoma under three years of age based on methylation molecule type

Background Medulloblastoma (MB), a prevalent malignant pediatric brain tumor, typically necessitates a comprehensive treatment regimen. However, the standard treatment paradigm is often not viable for infants (< 3 years old) incomplete, which contraindicates traditional radiotherapy. This study retrospectively analyzed the efficacy of chemotherapy with deferred radiotherapy in infants. Methods The cohort consisted of 23 infants who receiving surgical resection of MB, which has been categorized into SHH, Group_3, and Group_4 subgroups and received postoperative chemotherapy. Molecular subgroups were identified using DNA methylation sequencing. This study analyzed the overall survival and recurrence rates based on molecular subgroup and evaluated the effects of treatment strategies. Results SHH accounted for 48%, Group_3 for 40%, and Group_4 for 12%. The follow-up period ranged from 1 to 131 months, with a median of 51 months. The overall survival rate was 60%, with survival rates for SHH, Group_3, and Group_4 at 66.7%, 50.0%, and 66.7%, respectively. The survival rates at 1, 3, 5, and 10 years were 92%, 80%, 48%, and 12%, respectively. Univariate and multivariate Cox regression analyses indicated that recurrence and treatment modalities significantly impacted survival times, with a hazard ratio of 10.28 for recurrence (95% CI: 1.99–53.03, p = 0.005) and 4.59 for chemotherapy alone (95% CI: 1.11–18.93, p = 0.035). The findings suggest that for infants with MB, a combined treatment approach of postoperative chemotherapy followed by delayed radiotherapy significantly improves overall survival compared to chemotherapy alone. Conclusion The findings suggest that infants with MB benefit substantially from postoperative chemotherapy followed by delayed radiotherapy.