Combined radiotherapy and chemotherapy for pediatric medulloblastoma: a clinical study of 33 cases

Abstract

Objective To retrospectively review the clinical characteristics of medulloblastoma,discuss the optimized treatment regimen,and analyze the prognostic influential factors.Methods Thirty-three children with pathologically certified medulloblastoma(aged 3-14 years with average of 6.5 years),admitted from Aug.2004 to Dec.2007,received radiotherapy within 3 weeks post surgery.Ratiotherapy consisted of 28~36Gy whole craniospinal radiation and a supplementary radiation aimed at tumors by three-dimensional conformal radiotherapy(3D-CRT) for a total dose of 50~54Gy(conventional fraction dose of 1.8-2.0Gy).A part of patients received hyperfractionation radiotherapy(1.0Gy/f,2f/d) for alleviating the tardive adverse events.Meanwhile,a synchronized chemotherapy,consisting of lomustine + vincristine + cisplatin,or isophosphamide + carboplatin + etoposide,was administered after the completion of whole craniospinal radiation,and 3-5 courses of sequential chemotherapy were given after the overall radiotherapy was finished.According to the metastasis,and the residual tumor and its size,the 33 patients were divided into 2 groups as follows: low-risk group(n=24): no metastases,total or sub-total excision of tumors(residual tumors ≤1.5cm3);high-risk group(n=9): either metastases or residual tumor > 1.5cm3.The 3-year survival rates of two groups were then compared.Results The combined radiotherapy and chemotherapy was effective to 10 of the 11 patients(90.9%) with residual tumors.Out of the 33 patients,31 obtained complete remission(93.9%),and 2 patients showed partial remission or stable status(3.0%,respectively).The median survival time of 33 patients was 51 months,3-year disease free survival(DFS) was 75.8%,and 3-year overall survival(OS) was 78.8%,including 33.3% in high-risk group and 95.8% in low-risk group(P < 0.01).The major side effects occurred in haematological system and digestive system,such as an incidence of 21.2%(7/33) with grade Ⅲ-Ⅳ bone marrow suppression,87.9%(29/33) with nausea,and 66.7%(22/33) with nausea and vomiting.Conclusions It is not difficult to make a definite diagnosis of pediatric medulloblastoma.Combined radiotherapy and chemotherapy following surgery,which is primarily recommended therapy,will give favorable effects with a low risk of complicating severe adverse events.The eradication of the tumor plays a pivotal role in influencing the prognosis of patients.