Long-Term Outcomes of Radiotherapy for Primary Pediatric Brain Tumors: Statistics and Strategies of a Single Institute in Taiwan

Purpose In Taiwan, data regarding the long-term outcomes of radiotherapy for pediatric brain tumors are still rare. We developed an electronic registry system (ERS) that can help to establish a database, which consisted of 986 cases of primary brain tumors in children younger than 18 years of age in Taipei Veterans General Hospital from January 1975 to May 2004. In this study, we focused on the long-term outcomes of 371 available patients treated by radiotherapy.
Materials and Methods: In our original cancer registry data, there were 529 pediatric brain tumor patients who underwent radiotherapy between January 1975 and May 2004. However, after reviewing the cases, only 371 cases (70.1%) were fully recorded without missing data. Profiles of radiotherapy for these patients were input into our newly established ERS. The demographic data were analyzed, including classification of tumors, gender distribution, mortality case numbers after radiotherapy, age at treatment, dose profile of radiotherapy, and proportion of patients receiving radiotherapy. For some diseases of interest, overall survival, progression-free survival and postradiotherapy failure-free survival were also analyzed by the Kaplan-Meier method.
Results: Of the 371 patients receiving radiotherapy, treatment for medulloblastomas is the most common (n=93), followed by germinomas (n=59), astrocytomas (n=36), anaplastic astrocytomas (n=36) and brain stem tumors (n=29). The proportions of patients receiving radiotherapy for medulloblastomas, atypical teratoid/rhabdoid tumors, astrocytomas (grade Ⅱ), anaplastic astrocytomas, glioblastomas and germinomas were 70.9%, 90.4%, 48.65%, 80.0%, 41.0% and 78.6%, respectively. The pooled mortality rate of all diseases after radiotherapy was 43.93%. The five-year overall survival rates of medulloblastomas, astrocytomas (grade Ⅱ), anaplastic astrocytomas and germinomas were 81.73%, 71.49%, 25.34% and 88.94%, respectively. The 5-year progression-free survival of medulloblastomas was 66.46%. Additionally, seven patients (1.89%) suffered from radiation-induced secondary tumors after completion of radiotherapy for a period of time (range, 2.8 to 24 years; median, 19.7 years).
Conclusion: An electronic registry system can help to facilitate the statistical analysis for rare pediatric brain tumor data. Our demographic and survival analyses were mostly comparable with those of previous studies. The database of pediatric brain tumors is worthy continuing to provide materials for further studies.