To retrospectively analyze the impacts of a craniospinal radiation dose ≤24 Gy or>24 Gy on the prognosis of patients with average-risk medulloblastoma.

Average-risk medulloblastoma was defined as non-metastatic cancer in children more than 3 years old with complete or near-complete (residual tumor ≤1.5 cm³) resection of tumor. A total of 72 children and adolescents with newly diagnosed average-risk medulloblastoma were enrolled as subjects from 2003 to 2013. After radical resection of the tumor, all patients received craniospinal plus local tumor bed radiotherapy and 8 cycles of adjuvant chemotherapy using cisplatin-, semustine-, or plus vincristine-based regimens. Patients exposed to a radiation dose ≤24 Gy were enrolled into Group A (n=20), while patients exposed to a radiation dose>24 Gy were enrolled into Group B (n=52). The recurrence rate and survival rate were compared between the two groups. The recurrence rate and survival rate were calculated using the Kaplan-Meier method and the differences between the two groups were analyzed using the log-rank test.

Patients in Group A and Group B received craniospinal radiotherapy with a dose of 19.2-24.0 Gy and 24.1-30.6 Gy, respectively. After radiotherapy, 66 patients (92%) completed all adjuvant chemotherapy. A total of 11 patients were recurrence. In all patients, the 3-year sample size was 48; the 3-year event-free survival (EFS) and overall survival (OS) rates were 83% and 86%, respectively. There were no significant differences in the 3-year EFS and OS rates between Group A and Group B (84% vs. 83%, P=0.609; 85% vs. 87%, P=0.963).

The standard comprehensive therapy achieves satisfactory treatment outcomes for average-risk medulloblastoma, in which a craniospinal radiation dose decreased to 19.2-24.0 Gy has no impacts on treatment outcomes.

Medulloblastoma, average-risk/radiotherapy; Medulloblastoma, average-risk/chemotherapy; Prognosis