Medulloblastoma, a primitive neuroectodermal tumor growing in cerebellum, is one of the most sensitive to radiation therapy childhood brain tumors, therefore, this method of treatments is justly considered to be the standard for the treatment of medulloblastoma. The outcome of this malignant brain tumor differs in standard and high-risk groups of patients. The aim of the work was to evaluate the survival rate for children with medulloblastoma according to two risk groups.
Patients and methods: Eighteen patients aged from 3 to 18 years with histological proven medulloblastoma treated with standard craniospinal and additional posterior fossa radiotherapy were investigated in our study. Nine patients with disseminated and partial removed medulloblastoma were assigned to the high-risk group and other 9 patients with local ant totally removed medulloblastoma were allocated to the standard risk group.
Results: Radiological response of medulloblastoma to the radiation therapy was observed in 15 (83.3%) out of 18 patients: complete radiological response was observed in 6 (67%) out of 9 standard-risk patients and in only 1 (11.1%) out of 9 high-risk patients (p<0.05). Medulloblastoma progressed in 15 (83.3%) patients treated with radiation therapy: relapse rate in the high-risk group was 100% and in the standard-risk group--66.7% (p>0.05). The mean time to progression for all patients was 18.2 months: 28.9 months in standard and 7.4 months in high-risk group (p=0.02). The overall survival for all investigated patients was 25.8 months: 37.2 and 14.3 months in the standard and high-risk groups, respectively (p=0.01). Five years progression-free and overall survival rate for all patients was 16.7%: 0% in the high-risk group and 33.3 % in the standard-risk group (p>0.05).
Conclusion: In our study the difference in survival rate between standard and high-risk patients with medulloblastoma was shown. We observed a statistically significant longer time to progression and better overall survival in the standard-risk group. However, we did not find any significant differences in other survival indices (response, relapse rates, mortality, five years progression- free and overall survival) between those two risk groups.